diff --git a/lib/middleware/cache.js b/lib/middleware/cache.js
index 2a50251e3c..4877937662 100644
--- a/lib/middleware/cache.js
+++ b/lib/middleware/cache.js
@@ -40,7 +40,7 @@ module.exports = function(app, options = {}) {
                     if (value) {
                         await redisClient.expire(key, 24 * 60 * 60);
                     }
-                    return value;
+                    return value + '';
                 }
             },
             set: async function(key, value, maxAge = 24 * 60 * 60) {
@@ -81,7 +81,7 @@ module.exports = function(app, options = {}) {
         app.context.cache = {
             get: (key) => {
                 if (key) {
-                    return routeCache.get(key);
+                    return routeCache.get(key) + '';
                 }
             },
             set: (key, value, maxAge = 24 * 60 * 60) => {
diff --git a/lib/middleware/parameter.js b/lib/middleware/parameter.js
index bb03590268..62a3ec0152 100644
--- a/lib/middleware/parameter.js
+++ b/lib/middleware/parameter.js
@@ -5,12 +5,12 @@ module.exports = async (ctx, next) => {
 
     // decode HTML entities
     if (ctx.state.data) {
-        ctx.state.data.title && (ctx.state.data.title = he.decode(ctx.state.data.title));
-        ctx.state.data.description && (ctx.state.data.description = he.decode(ctx.state.data.description));
+        ctx.state.data.title && (ctx.state.data.title = he.decode(ctx.state.data.title + ''));
+        ctx.state.data.description && (ctx.state.data.description = he.decode(ctx.state.data.description + ''));
         ctx.state.data.item &&
             ctx.state.data.item.forEach((item) => {
-                item.title && (item.title = he.decode(item.title));
-                item.description && (item.description = he.decode(item.description));
+                item.title && (item.title = he.decode(item.title + ''));
+                item.description && (item.description = he.decode(item.description + ''));
             });
     }