diff --git a/packages/db/migrations/0088_log_audit_at_index.ts b/packages/db/migrations/0088_log_audit_at_index.ts
new file mode 100644
index 00000000..2dbcd1c9
--- /dev/null
+++ b/packages/db/migrations/0088_log_audit_at_index.ts
@@ -0,0 +1,17 @@
+import type { Kysely } from "kysely";
+import { execDdl } from "../src/migration-helpers.ts";
+
+// 日志接口:审计来源按时间倒序取前 n 条,原有索引都以 action / actor / target 开头,只能整表排序;
+// 补一个按时间的索引(审计会随登录、设置修改一直增长)。
+// 引擎表 openworkflow.workflow_runs 不在这里加索引:引擎自带 (namespace_id, created_at desc) 与
+// (namespace_id, status, created_at desc),日志查询已能沿用。
+
+// biome-ignore lint/suspicious/noExplicitAny: 迁移不依赖应用表类型
+export async function up(db: Kysely<any>): Promise<void> {
+  await execDdl(db, `create index if not exists audit_event_at_idx on audit_event (at desc);`);
+}
+
+// biome-ignore lint/suspicious/noExplicitAny: 同上
+export async function down(db: Kysely<any>): Promise<void> {
+  await execDdl(db, `drop index if exists audit_event_at_idx;`);
+}