diff --git a/packages/docsify-server-renderer/index.js b/packages/docsify-server-renderer/index.js
index 6921854a..0b667b6f 100644
--- a/packages/docsify-server-renderer/index.js
+++ b/packages/docsify-server-renderer/index.js
@@ -130,7 +130,6 @@ export default class Renderer {
       }
 
       const fileName = basename(filePath)
-      const parentPath = cwd(filePath, '../..')
 
       await this._loadFile(cwd(filePath, '../..', fileName))
     }
diff --git a/src/core/render/index.js b/src/core/render/index.js
index 6958bbec..4b5d2a10 100644
--- a/src/core/render/index.js
+++ b/src/core/render/index.js
@@ -143,7 +143,7 @@ export function renderMixin (proto) {
 
         dom.toggleClass(el, 'add', 'has-mask')
         if (!isAbsolutePath(m[1])) {
-          path = getPath(vm.router.getBasePath(), m[1])
+          path = getPath(this.router.getBasePath(), m[1])
         }
         el.style.backgroundImage = `url(${path})`
         el.style.backgroundSize = 'cover'
diff --git a/src/core/router/history/base.js b/src/core/router/history/base.js
index cb24826a..ca914a3b 100644
--- a/src/core/router/history/base.js
+++ b/src/core/router/history/base.js
@@ -18,7 +18,7 @@ export class History {
     this.config = config
   }
 
-  getBasePath() {
+  getBasePath () {
     return this.config.basePath
   }
 
diff --git a/src/core/router/history/hash.js b/src/core/router/history/hash.js
index 696b5530..5dce5a7a 100644
--- a/src/core/router/history/hash.js
+++ b/src/core/router/history/hash.js
@@ -20,7 +20,7 @@ export class HashHistory extends History {
     this.mode = 'hash'
   }
 
-  getBasePath() {
+  getBasePath () {
     const path = window.location.pathname || ''
     const base = this.config.basePath