diff --git a/src/main/java/com/genersoft/iot/vmp/aiot/service/impl/AiScreenshotServiceImpl.java b/src/main/java/com/genersoft/iot/vmp/aiot/service/impl/AiScreenshotServiceImpl.java
index ddad80594..478469f3a 100644
--- a/src/main/java/com/genersoft/iot/vmp/aiot/service/impl/AiScreenshotServiceImpl.java
+++ b/src/main/java/com/genersoft/iot/vmp/aiot/service/impl/AiScreenshotServiceImpl.java
@@ -210,8 +210,15 @@ public class AiScreenshotServiceImpl implements IAiScreenshotService {
             String url = (String) data.get("url");
             writeCache(cameraCode, url);
 
-            // 持久化 cos_key 到 DB（永不过期，供后续直接读取）
-            String cosKey = pendingCosKeys.remove(requestId);
+            // 从URL解析cos_key（优先），失败时降级使用pendingCosKeys
+            String cosKey = extractCosKeyFromUrl(url);
+            if (cosKey == null) {
+                cosKey = pendingCosKeys.remove(requestId);
+            } else {
+                // 解析成功，也要清理pendingCosKeys避免内存泄漏
+                pendingCosKeys.remove(requestId);
+            }
+
             if (cosKey != null) {
                 try {
                     snapshotMapper.upsert(cameraCode, cosKey);
@@ -219,6 +226,8 @@ public class AiScreenshotServiceImpl implements IAiScreenshotService {
                 } catch (Exception e) {
                     log.error("[AI截图] 持久化 cos_key 失败: cameraCode={}, error={}", cameraCode, e.getMessage());
                 }
+            } else {
+                log.warn("[AI截图] 无法获取cos_key: cameraCode={}, url={}", cameraCode, url);
             }
         } else {
             pendingCosKeys.remove(requestId);
@@ -233,6 +242,48 @@ public class AiScreenshotServiceImpl implements IAiScreenshotService {
         }
     }
 
+    /**
+     * 从COS预签名URL中提取cos_key
+     * URL格式: https://{bucket}.cos.{region}.myqcloud.com/{cos_key}?q-sign-...
+     * 返回: snapshots/{camera_code}/2026-03-10/08-16-39_xxx.jpg
+     */
+    private String extractCosKeyFromUrl(String url) {
+        if (url == null || url.isEmpty()) {
+            return null;
+        }
+        try {
+            // 移除查询参数，得到路径部分
+            String pathPart = url;
+            int queryStart = url.indexOf('?');
+            if (queryStart > 0) {
+                pathPart = url.substring(0, queryStart);
+            }
+
+            // 找到myqcloud.com后的路径
+            int domainEnd = pathPart.indexOf(".myqcloud.com/");
+            if (domainEnd > 0) {
+                String cosKey = pathPart.substring(domainEnd + ".myqcloud.com/".length());
+                // 确保以snapshots/开头
+                if (cosKey.startsWith("snapshots/")) {
+                    return cosKey;
+                }
+            }
+
+            // 降级：尝试最后一个/后的路径
+            int lastSlash = pathPart.lastIndexOf('/');
+            if (lastSlash > 0) {
+                // 往回找snapshots
+                int snapshotsIdx = pathPart.indexOf("snapshots/");
+                if (snapshotsIdx > 0) {
+                    return pathPart.substring(snapshotsIdx);
+                }
+            }
+        } catch (Exception e) {
+            log.warn("[AI截图] 从URL解析cos_key失败: {}, error={}", url, e.getMessage());
+        }
+        return null;
+    }
+
     /**
      * 写入截图缓存
      */