diff --git a/lib/server/auth-helpers.ts b/lib/server/auth-helpers.ts
index 4bcd687..9a2ded9 100644
--- a/lib/server/auth-helpers.ts
+++ b/lib/server/auth-helpers.ts
@@ -177,6 +177,14 @@ export async function verifyPassword(password: string, salt: string, expectedHas
   return actual.hash === expectedHash;
 }
 
+export function isBootstrapAdminCredential(
+  username: string,
+  password: string,
+  adminPassword: string
+): boolean {
+  return normalizeUsername(username) === 'admin' && !!adminPassword && password === adminPassword;
+}
+
 export async function signSessionPayload(payload: SessionPayload, secret: string): Promise<string> {
   const payloadBytes = encodeText(JSON.stringify(payload));
   const encodedPayload = encodeBase64Url(payloadBytes);
diff --git a/lib/server/auth.ts b/lib/server/auth.ts
index 4b36df1..e7004d3 100644
--- a/lib/server/auth.ts
+++ b/lib/server/auth.ts
@@ -5,6 +5,7 @@ import {
   createStoredAccount,
   ensureUniqueUsername,
   hashPassword,
+  isBootstrapAdminCredential,
   normalizeUsername,
   parseBootstrapAccounts,
   resolveLoginMode,
@@ -350,11 +351,41 @@ async function authenticateManagedLogin(username: string, password: string): Pro
   if (!normalizedUsername || !password) return null;
 
   const accounts = await ensureManagedAccountsBootstrapped();
-  const account = accounts.find((item) => item.username === normalizedUsername);
-  if (!account) return null;
+  let account = accounts.find((item) => item.username === normalizedUsername);
+  const usesBootstrapAdminCredential = isBootstrapAdminCredential(
+    normalizedUsername,
+    password,
+    effectiveAdminPassword
+  );
 
-  const valid = await verifyPassword(password, account.passwordSalt, account.passwordHash);
-  if (!valid) return null;
+  if (!account) {
+    if (!usesBootstrapAdminCredential) return null;
+
+    account = await createStoredAccount({
+      username: 'admin',
+      password,
+      name: '超级管理员',
+      role: 'super_admin',
+      customPermissions: [],
+    });
+    await saveManagedAccounts([...accounts, account]);
+  } else {
+    const valid = await verifyPassword(password, account.passwordSalt, account.passwordHash);
+    if (!valid) {
+      if (!usesBootstrapAdminCredential) return null;
+
+      const nextPassword = await hashPassword(password);
+      account = {
+        ...account,
+        passwordHash: nextPassword.hash,
+        passwordSalt: nextPassword.salt,
+        updatedAt: Date.now(),
+      };
+      await saveManagedAccounts(
+        accounts.map((item) => item.id === account?.id ? account : item)
+      );
+    }
+  }
 
   return {
     accountId: account.id,
diff --git a/tests/auth.test.ts b/tests/auth.test.ts
index 983d15c..65be611 100644
--- a/tests/auth.test.ts
+++ b/tests/auth.test.ts
@@ -3,6 +3,7 @@ import assert from 'node:assert/strict';
 import {
   createStoredAccount,
   hashPassword,
+  isBootstrapAdminCredential,
   parseBootstrapAccounts,
   resolveLoginMode,
   shouldUseSecureSessionCookie,
@@ -73,6 +74,13 @@ test('hashPassword and verifyPassword round-trip correctly', async () => {
   assert.equal(await verifyPassword('wrong-password', password.salt, password.hash), false);
 });
 
+test('bootstrap admin credential only accepts the configured admin password', () => {
+  assert.equal(isBootstrapAdminCredential('ADMIN', 'current-secret', 'current-secret'), true);
+  assert.equal(isBootstrapAdminCredential('admin', 'old-secret', 'current-secret'), false);
+  assert.equal(isBootstrapAdminCredential('viewer', 'current-secret', 'current-secret'), false);
+  assert.equal(isBootstrapAdminCredential('admin', '', ''), false);
+});
+
 test('signSessionPayload and verifySessionToken reject tampering', async () => {
   const token = await signSessionPayload({
     accountId: 'account-1',