diff --git a/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/AppSessionSystemService.java b/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/AppSessionSystemService.java
index ec7b7dd..b866b7b 100644
--- a/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/AppSessionSystemService.java
+++ b/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/AppSessionSystemService.java
@@ -15,6 +15,7 @@ import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 
 /**
@@ -62,6 +63,31 @@ public class AppSessionSystemService {
         return result;
     }
 
+    /**
+     * 平台筛选的命中范围：设备平台直接给 device_id；登录用户的行为行不带 device_id，
+     * 只能按该用户登录会话的平台判定，两者取并集。
+     */
+    public record PlatformScope(List<String> deviceIds, List<Long> userIds) {
+        public boolean empty() {
+            return deviceIds.isEmpty() && userIds.isEmpty();
+        }
+    }
+
+    /** 按平台解析命中范围；未传平台返回 null 表示不限制。 */
+    public PlatformScope platformScope(String platform) {
+        if (!StringUtils.hasText(platform)) {
+            return null;
+        }
+        String value = platform.trim().toUpperCase(Locale.ROOT);
+        List<String> deviceIds = profileMapper.selectList(Wrappers.<AppDeviceProfile>lambdaQuery()
+                        .select(AppDeviceProfile::getDeviceId)
+                        .eq(AppDeviceProfile::getPlatform, value))
+                .stream().map(AppDeviceProfile::getDeviceId).toList();
+        // 只认「最近一次登录」的平台，与列表里展示的系统保持一致
+        List<Long> userIds = sessionMapper.selectUserIdsByLatestPlatform(value);
+        return new PlatformScope(deviceIds, userIds);
+    }
+
     /** 观看记录优先匹配同一设备，其次取未吊销会话。 */
     public AppUserSession match(List<AppUserSession> sessions, String deviceId) {
         if (sessions == null || sessions.isEmpty()) {
diff --git a/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/EngagementAdminLookup.java b/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/EngagementAdminLookup.java
index d4421dc..d6b150c 100644
--- a/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/EngagementAdminLookup.java
+++ b/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/EngagementAdminLookup.java
@@ -21,6 +21,7 @@ import org.springframework.util.StringUtils;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
 import java.util.function.Function;
@@ -42,6 +43,7 @@ public class EngagementAdminLookup {
     private final DramaMapper dramaMapper;
     private final AppDeviceProfileMapper deviceProfileMapper;
     private final AppUserSessionMapper sessionMapper;
+    private final AppSessionSystemService sessionSystem;
 
     /** 规范化页码和页大小。 */
     public <T> Page<T> page(EngagementQueryReqVO req) {
@@ -132,6 +134,11 @@ public class EngagementAdminLookup {
         return result;
     }
 
+    /** 按平台解析命中范围；未传平台返回 null 表示不限制。 */
+    public AppSessionSystemService.PlatformScope platformScope(String platform) {
+        return sessionSystem.platformScope(platform);
+    }
+
     private List<Long> keys(Collection<Long> ids) {
         return ids.stream().filter(Objects::nonNull).distinct().toList();
     }
diff --git a/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/FavoriteAdminService.java b/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/FavoriteAdminService.java
index 8193480..f9eb55b 100644
--- a/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/FavoriteAdminService.java
+++ b/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/FavoriteAdminService.java
@@ -36,6 +36,10 @@ public class FavoriteAdminService {
         if (lookup.noMatch(dramaIds)) {
             return PageResult.empty();
         }
+        var scope = lookup.platformScope(req.getPlatform());
+        if (scope != null && scope.empty()) {
+            return PageResult.empty();
+        }
         var query = Wrappers.<UserFavorite>lambdaQuery()
                 .eq(req.getUserId() != null, UserFavorite::getUserId, req.getUserId())
                 .in(userIds != null, UserFavorite::getUserId, userIds)
@@ -43,8 +47,22 @@ public class FavoriteAdminService {
                 .eq(req.getDramaId() != null, UserFavorite::getDramaId, req.getDramaId())
                 .in(dramaIds != null, UserFavorite::getDramaId, dramaIds)
                 .ge(req.getStartTime() != null, UserFavorite::getCreatedAt, req.getStartTime())
-                .le(req.getEndTime() != null, UserFavorite::getCreatedAt, req.getEndTime())
-                .orderByDesc(UserFavorite::getCreatedAt, UserFavorite::getId);
+                .le(req.getEndTime() != null, UserFavorite::getCreatedAt, req.getEndTime());
+        // orderBy 必须最后追加，否则条件会被拼到 ORDER BY 后面
+        if (scope != null) {
+            query.and(inner -> {
+                if (!scope.deviceIds().isEmpty()) {
+                    inner.in(UserFavorite::getDeviceId, scope.deviceIds());
+                }
+                if (!scope.userIds().isEmpty()) {
+                    if (!scope.deviceIds().isEmpty()) {
+                        inner.or();
+                    }
+                    inner.in(UserFavorite::getUserId, scope.userIds());
+                }
+            });
+        }
+        query.orderByDesc(UserFavorite::getCreatedAt, UserFavorite::getId);
         var result = favoriteMapper.selectPage(lookup.page(req), query);
         return new PageResult<>(result.getTotal(), assemble(result.getRecords()));
     }
diff --git a/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/LikeAdminService.java b/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/LikeAdminService.java
index 4520750..4f87d8c 100644
--- a/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/LikeAdminService.java
+++ b/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/LikeAdminService.java
@@ -69,6 +69,23 @@ public class LikeAdminService {
             return PageResult.empty();
         }
         var query = buildQuery(req, users);
+        var scope = lookup.platformScope(req.getPlatform());
+        if (scope != null && scope.empty()) {
+            return PageResult.empty();
+        }
+        if (scope != null) {
+            query.and(inner -> {
+                if (!scope.deviceIds().isEmpty()) {
+                    inner.in(ContentLike::getDeviceId, scope.deviceIds());
+                }
+                if (!scope.userIds().isEmpty()) {
+                    if (!scope.deviceIds().isEmpty()) {
+                        inner.or();
+                    }
+                    inner.in(ContentLike::getUserId, scope.userIds());
+                }
+            });
+        }
         if (req.getDramaId() != null) {
             query.and(q -> q.apply(DRAMA_MATCH, req.getDramaId()));
         }
@@ -82,6 +99,8 @@ public class LikeAdminService {
         if (req.getEpisodeId() != null) {
             query.and(q -> q.apply(EPISODE_MATCH, req.getEpisodeId()));
         }
+        // orderBy 必须最后追加，否则条件会被拼到 ORDER BY 后面
+        query.orderByDesc(ContentLike::getCreatedAt, ContentLike::getId);
         var result = likeMapper.selectPage(lookup.page(req), query);
         return new PageResult<>(result.getTotal(), assemble(result.getRecords()));
     }
@@ -94,8 +113,7 @@ public class LikeAdminService {
                 .eq(StringUtils.hasText(req.getTargetType()), ContentLike::getTargetType, req.getTargetType())
                 .eq(req.getTargetId() != null, ContentLike::getTargetId, req.getTargetId())
                 .ge(req.getStartTime() != null, ContentLike::getCreatedAt, req.getStartTime())
-                .le(req.getEndTime() != null, ContentLike::getCreatedAt, req.getEndTime())
-                .orderByDesc(ContentLike::getCreatedAt, ContentLike::getId);
+                .le(req.getEndTime() != null, ContentLike::getCreatedAt, req.getEndTime());
     }
 
     private List<AdminLikeVO> assemble(List<ContentLike> rows) {
diff --git a/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/WatchHistoryAdminService.java b/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/WatchHistoryAdminService.java
index 8ec7f45..4afbcbd 100644
--- a/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/WatchHistoryAdminService.java
+++ b/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/service/WatchHistoryAdminService.java
@@ -66,14 +66,19 @@ public class WatchHistoryAdminService {
         if (matchedDramaIds != null && matchedDramaIds.isEmpty()) {
             return emptyPage();
         }
+        var scope = sessionSystem.platformScope(req.getPlatform());
+        if (scope != null && scope.empty()) {
+            return emptyPage();
+        }
         IPage<WatchHistory> result = watchHistoryMapper.selectPage(new Page<>(pageIndex, pageSize),
-                buildQuery(req, matchedUserIds, matchedDramaIds));
+                buildQuery(req, matchedUserIds, matchedDramaIds, scope));
         return new PageResult<>(result.getTotal(), toVoList(result.getRecords()));
     }
 
     private LambdaQueryWrapper<WatchHistory> buildQuery(WatchHistoryQueryReqVO req,
                                                         List<Long> matchedUserIds,
-                                                        List<Long> matchedDramaIds) {
+                                                        List<Long> matchedDramaIds,
+                                                        AppSessionSystemService.PlatformScope scope) {
         LambdaQueryWrapper<WatchHistory> wrapper = Wrappers.<WatchHistory>lambdaQuery()
                 .eq(req.getUserId() != null, WatchHistory::getUserId, req.getUserId())
                 .in(matchedUserIds != null, WatchHistory::getUserId, matchedUserIds)
@@ -83,6 +88,19 @@ public class WatchHistoryAdminService {
                 .eq(StringUtils.hasText(req.getSource()), WatchHistory::getSource, req.getSource())
                 .ge(req.getStartTime() != null, WatchHistory::getWatchedAt, req.getStartTime())
                 .le(req.getEndTime() != null, WatchHistory::getWatchedAt, req.getEndTime());
+        if (scope != null) {
+            wrapper.and(inner -> {
+                if (!scope.deviceIds().isEmpty()) {
+                    inner.in(WatchHistory::getDeviceId, scope.deviceIds());
+                }
+                if (!scope.userIds().isEmpty()) {
+                    if (!scope.deviceIds().isEmpty()) {
+                        inner.or();
+                    }
+                    inner.in(WatchHistory::getUserId, scope.userIds());
+                }
+            });
+        }
         applyFinished(wrapper, req.getFinished());
         return wrapper.orderByDesc(WatchHistory::getWatchedAt)
                 .orderByDesc(WatchHistory::getId);
diff --git a/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/vo/EngagementQueryReqVO.java b/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/vo/EngagementQueryReqVO.java
index 4391bba..849c726 100644
--- a/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/vo/EngagementQueryReqVO.java
+++ b/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/vo/EngagementQueryReqVO.java
@@ -16,6 +16,8 @@ public class EngagementQueryReqVO {
     private String keyword;
     private Long userId;
     private String deviceId;
+    /** 客户端平台筛选：ANDROID / IOS / WEB，留空不限制。 */
+    private String platform;
     private String dramaTitle;
     private Long dramaId;
     @DateTimeFormat(pattern = TIME_PATTERN)
diff --git a/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/vo/WatchHistoryQueryReqVO.java b/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/vo/WatchHistoryQueryReqVO.java
index ef26d7b..bde569c 100644
--- a/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/vo/WatchHistoryQueryReqVO.java
+++ b/fruitshorts-admin-api/src/main/java/com/fruitshorts/admin/vo/WatchHistoryQueryReqVO.java
@@ -20,6 +20,8 @@ public class WatchHistoryQueryReqVO {
     private String dramaTitle;
     private Long dramaId;
     private Long episodeId;
+    /** 客户端平台筛选：ANDROID / IOS / WEB，留空不限制。 */
+    private String platform;
     private String source;
     private Boolean finished;
 
diff --git a/fruitshorts-module-user/src/main/java/com/fruitshorts/user/dal/mapper/AppUserSessionMapper.java b/fruitshorts-module-user/src/main/java/com/fruitshorts/user/dal/mapper/AppUserSessionMapper.java
index e27d100..a5cf71a 100644
--- a/fruitshorts-module-user/src/main/java/com/fruitshorts/user/dal/mapper/AppUserSessionMapper.java
+++ b/fruitshorts-module-user/src/main/java/com/fruitshorts/user/dal/mapper/AppUserSessionMapper.java
@@ -4,6 +4,27 @@ package com.fruitshorts.user.dal.mapper;
 
 import com.baomidou.mybatisplus.core.mapper.BaseMapper;
 import com.fruitshorts.user.dal.entity.AppUserSession;
+import org.apache.ibatis.annotations.Param;
+import org.apache.ibatis.annotations.Select;
+
+import java.util.List;
 
 public interface AppUserSessionMapper extends BaseMapper<AppUserSession> {
+
+    /**
+     * 最近一次登录会话平台等于指定值的用户。
+     * 必须取「最近一次」而不是「存在过」：否则同一用户在 Android 登录过、
+     * 后来又换 iOS，会被两端都命中，筛选结果与实际展示的系统不一致。
+     */
+    @Select("""
+            SELECT t.user_id
+            FROM (
+                SELECT DISTINCT ON (user_id) user_id, platform
+                FROM app_user_session
+                WHERE deleted = 0
+                ORDER BY user_id, last_active_at DESC NULLS LAST, id DESC
+            ) t
+            WHERE t.platform = #{platform}
+            """)
+    List<Long> selectUserIdsByLatestPlatform(@Param("platform") String platform);
 }