diff --git a/server/app/adminapi/logic/stats/ConversionLogic.php b/server/app/adminapi/logic/stats/ConversionLogic.php
index a78ffe8d..35a7cc7c 100644
--- a/server/app/adminapi/logic/stats/ConversionLogic.php
+++ b/server/app/adminapi/logic/stats/ConversionLogic.php
@@ -67,7 +67,10 @@ class ConversionLogic
         $supportsDeptBinding = AccountCost::supportsDeptBinding();
         $restrictAccountCostByDept = $supportsDeptBinding;
         $restrictStatsByDept = $supportsDeptBinding && $mediaChannelCode !== '';
-        $eligibleDeptIds = $restrictAccountCostByDept ? self::expandDeptIdsWithDescendants($accountCostDeptIds) : $accountCostDeptIds;
+        $scopeDeptIds = $restrictStatsByDept
+            ? self::loadChannelBoundDeptIds($mediaChannelCode)
+            : $accountCostDeptIds;
+        $eligibleDeptIds = $restrictAccountCostByDept ? self::expandDeptIdsWithDescendants($scopeDeptIds) : $scopeDeptIds;
 
         if ($restrictStatsByDept) {
             $entities = self::filterEntitiesByChannelDeptScope($entities, $dimension, $eligibleDeptIds, $adminToDeptIds);
@@ -440,6 +443,27 @@ class ConversionLogic
         return array_values($expanded);
     }
 
+    /**
+     * 渠道绑定部门不依赖当前统计区间，避免某天没有录入成本时把统计实体过滤为空。
+     *
+     * @return int[]
+     */
+    private static function loadChannelBoundDeptIds(string $mediaChannelCode): array
+    {
+        $mediaChannelCode = trim($mediaChannelCode);
+        if ($mediaChannelCode === '' || !AccountCost::supportsDeptBinding()) {
+            return [];
+        }
+
+        $deptIds = Db::name('account_cost')
+            ->where('media_channel_code', $mediaChannelCode)
+            ->where('dept_id', '>', 0)
+            ->distinct(true)
+            ->column('dept_id');
+
+        return array_values(array_unique(array_filter(array_map('intval', $deptIds), static fn (int $deptId): bool => $deptId > 0)));
+    }
+
     /**
      * 自媒体渠道选中时，统计范围只允许落在渠道绑定部门及其子部门内。
      *