diff --git a/packages/@vuepress/core/__tests__/prepare/fixtures/docs-config/.vuepress/config.js b/packages/@vuepress/core/__tests__/prepare/fixtures/docs-config/.vuepress/config.js
index 665e1164b3..f4019472e5 100644
--- a/packages/@vuepress/core/__tests__/prepare/fixtures/docs-config/.vuepress/config.js
+++ b/packages/@vuepress/core/__tests__/prepare/fixtures/docs-config/.vuepress/config.js
@@ -1,6 +1,4 @@
 module.exports = {
-  title: 'Hello VuePress',
-  description: '# Hello, VuePress!',
   dest: 'vuepress',
   base: 'vuepress',
   head: [
diff --git a/packages/@vuepress/core/__tests__/prepare/fixtures/docs-config/.vuepress/config.yml b/packages/@vuepress/core/__tests__/prepare/fixtures/docs-config/.vuepress/config.yml
new file mode 100644
index 0000000000..d84b90de9e
--- /dev/null
+++ b/packages/@vuepress/core/__tests__/prepare/fixtures/docs-config/.vuepress/config.yml
@@ -0,0 +1,3 @@
+---
+title: Hello VuePress
+description: '# Hello, VuePress!'
diff --git a/packages/@vuepress/core/lib/prepare/loadConfig.js b/packages/@vuepress/core/lib/prepare/loadConfig.js
index c786e88d44..ad4cd45f79 100644
--- a/packages/@vuepress/core/lib/prepare/loadConfig.js
+++ b/packages/@vuepress/core/lib/prepare/loadConfig.js
@@ -24,11 +24,13 @@ module.exports = function loadConfig (vuepressDir, bustCache = true) {
   // resolve siteConfig
   let siteConfig = {}
   if (fs.existsSync(configYmlPath)) {
-    siteConfig = parseConfig(configYmlPath)
-  } else if (fs.existsSync(configTomlPath)) {
-    siteConfig = parseConfig(configTomlPath)
-  } else if (fs.existsSync(configPath)) {
-    siteConfig = require(configPath)
+    siteConfig = Object.assign(siteConfig, parseConfig(configYmlPath))
+  }
+  if (fs.existsSync(configTomlPath)) {
+    siteConfig = Object.assign(siteConfig, parseConfig(configTomlPath))
+  }
+  if (fs.existsSync(configPath)) {
+    siteConfig = Object.assign(siteConfig, require(configPath))
   }
 
   return siteConfig
diff --git a/packages/docs/docs/.vuepress/config.js b/packages/docs/docs/.vuepress/config.js
index b56d1334ed..a3d5d281ec 100755
--- a/packages/docs/docs/.vuepress/config.js
+++ b/packages/docs/docs/.vuepress/config.js
@@ -1,6 +1,6 @@
 const container = require('markdown-it-container')
 
-module.exports = ctx => ({
+module.exports = {
   dest: '../../vuepress',
   locales: {
     '/': {
@@ -63,7 +63,7 @@ module.exports = ctx => ({
     }
   },
   plugins: [
-    ['@vuepress/i18n-ui', !ctx.isProd],
+    ['@vuepress/i18n-ui'],
     ['@vuepress/back-to-top', true],
     ['@vuepress/pwa', {
       serviceWorker: true,
@@ -82,7 +82,7 @@ module.exports = ctx => ({
         : '</UpgradePath>'
     })
   },
-})
+}
 
 function getGuideSidebar (groupA, groupB) {
   return [
diff --git a/packages/docs/docs/guide/basic-config.md b/packages/docs/docs/guide/basic-config.md
index 5a17dbcd01..7ba7cfb13e 100644
--- a/packages/docs/docs/guide/basic-config.md
+++ b/packages/docs/docs/guide/basic-config.md
@@ -27,7 +27,7 @@ If you've got the dev server running, you should see the page now has a header w
 Consult the [Config Reference](../config/README.md) for a full list of options.
 
 ::: tip Alternative Config Formats
-You can also use YAML (`.vuepress/config.yml`) or TOML (`.vuepress/config.toml`) formats for the configuration file.
+You can also split config and use YAML (`.vuepress/config.yml`) or TOML (`.vuepress/config.toml`) formats for the configuration. All configuration files will be merged together.
 :::
 
 ## Theme Configuration