diff --git a/packages/@vue/cli-service/__tests__/Service.spec.js b/packages/@vue/cli-service/__tests__/Service.spec.js
index 9a0d769209..75c3e03d16 100644
--- a/packages/@vue/cli-service/__tests__/Service.spec.js
+++ b/packages/@vue/cli-service/__tests__/Service.spec.js
@@ -52,6 +52,18 @@ test('load project options from package.json', () => {
   expect(service.projectOptions.lintOnSave).toBe(true)
 })
 
+test('handle option baseUrl and outputDir correctly', () => {
+  mockPkg({
+    vue: {
+      baseUrl: 'https://foo.com/bar',
+      outputDir: '/public/'
+    }
+  })
+  const service = createMockService()
+  expect(service.projectOptions.baseUrl).toBe('https://foo.com/bar/')
+  expect(service.projectOptions.outputDir).toBe('public')
+})
+
 test('load project options from vue.config.js', () => {
   process.env.VUE_CLI_SERVICE_CONFIG_PATH = `/vue.config.js`
   fs.writeFileSync('/vue.config.js', `module.exports = { lintOnSave: false }`)
diff --git a/packages/@vue/cli-service/lib/Service.js b/packages/@vue/cli-service/lib/Service.js
index c903ff9aac..a2b1e776b0 100644
--- a/packages/@vue/cli-service/lib/Service.js
+++ b/packages/@vue/cli-service/lib/Service.js
@@ -222,10 +222,12 @@ module.exports = class Service {
 }
 
 function ensureSlash (config, key) {
-  if (typeof config[key] === 'string') {
-    config[key] = config[key]
-      .replace(/^([^/.])/, '/$1')
-      .replace(/([^/])$/, '$1/')
+  let val = config[key]
+  if (typeof val === 'string') {
+    if (!/^https?:/.test(val)) {
+      val = val.replace(/^([^/.])/, '/$1')
+    }
+    config[key] = val.replace(/([^/])$/, '$1/')
   }
 }