diff --git a/packages/@vuepress/core/lib/index.js b/packages/@vuepress/core/lib/index.js
index 85afa96123..31d0ad8576 100644
--- a/packages/@vuepress/core/lib/index.js
+++ b/packages/@vuepress/core/lib/index.js
@@ -11,12 +11,14 @@ function createApp (options) {
 
 async function dev (options) {
   const app = createApp(options)
+  app.isProd = false
   await app.process()
   return app.dev()
 }
 
 async function build (options) {
   const app = createApp(options)
+  app.isProd = true
   await app.process()
   return app.build()
 }
diff --git a/packages/@vuepress/core/lib/node/App.js b/packages/@vuepress/core/lib/node/App.js
index e21c8ce29b..797e81338f 100755
--- a/packages/@vuepress/core/lib/node/App.js
+++ b/packages/@vuepress/core/lib/node/App.js
@@ -459,7 +459,6 @@ module.exports = class App {
    */
 
   async dev () {
-    this.isProd = false
     this.devProcess = new DevProcess(this)
     await this.devProcess.process()
     const error = await new Promise(resolve => {
@@ -489,7 +488,6 @@ module.exports = class App {
    */
 
   async build () {
-    this.isProd = true
     this.buildProcess = new BuildProcess(this)
     await this.buildProcess.process()
     await this.buildProcess.render()