diff --git a/lib/config.js b/lib/config.js
index 7b2f70f80f..4df35f9dbf 100644
--- a/lib/config.js
+++ b/lib/config.js
@@ -13,7 +13,7 @@ module.exports = {
         socket: process.env.SOCKET || null, // 监听 Unix Socket, null 为禁用
     },
     cache: {
-        type: process.env.CACHE_TYPE === 'undefined' ? 'memory' : process.env.CACHE_TYPE, // 缓存类型，支持 'memory' 和 'redis'，设为空可以禁止缓存
+        type: typeof process.env.CACHE_TYPE === 'undefined' ? 'memory' : process.env.CACHE_TYPE, // 缓存类型，支持 'memory' 和 'redis'，设为空可以禁止缓存
         routeExpire: parseInt(process.env.CACHE_EXPIRE) || 5 * 60, // 路由缓存时间，单位为秒
         contentExpire: parseInt(process.env.CACHE_CONTENT_EXPIRE) || 1 * 60 * 60, // 不变内容缓存时间，单位为秒
     },
diff --git a/test/middleware/cache.js b/test/middleware/cache.js
index fa2eca42d1..91dac88df5 100644
--- a/test/middleware/cache.js
+++ b/test/middleware/cache.js
@@ -91,7 +91,7 @@ describe('cache', () => {
     });
 
     it('no cache', async () => {
-        delete process.env.CACHE_EXPIRE;
+        process.env.CACHE_TYPE = '';
         server = require('../../lib/index').server;
         const request = supertest(server);