diff --git a/scripts/database-backup-to-oss.mjs b/scripts/database-backup-to-oss.mjs
index 4b9031410..bc215509f 100644
--- a/scripts/database-backup-to-oss.mjs
+++ b/scripts/database-backup-to-oss.mjs
@@ -502,8 +502,12 @@ function acquireBackupLock({ workDir, database }) {
     ) {
       throw new Error(`已有数据库备份进程持有锁: ${lockPath} pid=${ownerPid}`);
     }
+    const staleLockPath = `${lockPath}.stale-${process.pid}-${attempt}-${Date.now()}`;
     try {
-      rmSync(lockPath);
+      // rename 是原子的：若另一个进程已先清理并重新建锁，这里只会得到 ENOENT，
+      // 不会把新进程的锁误删。
+      renameSync(lockPath, staleLockPath);
+      rmSync(staleLockPath, { force: true });
       console.log(
         `[database-backup] 已清理失效数据库备份锁，准备重新获取: ${lockPath} pid=${ownerPid || '<invalid>'}`,
       );