diff --git a/lib/commands/generate.js b/lib/commands/generate.js
index 95943dc..e1ef75e 100644
--- a/lib/commands/generate.js
+++ b/lib/commands/generate.js
@@ -6,6 +6,7 @@ const {cwd, exists} = require('../util')
 const path = require('path')
 const logger = require('../util/logger')
 const ignoreFiles = ['_navbar', '_coverpage', '_sidebar']
+const indent = '  '
 
 // eslint-disable-next-line
 module.exports = function (path = '', sidebar) {
@@ -16,7 +17,8 @@ module.exports = function (path = '', sidebar) {
       const sidebarPath = cwdPath + '/' + sidebar || '_sidebar.md'
 
       if (!exists(sidebarPath)) {
-        genSidebar(cwdPath, sidebarPath)
+        const lines = generateSidebar(cwdPath)
+        writeSidebar(lines, sidebarPath)
         logger.success(`Successfully generated the sidebar file '${sidebar}'.`)
         return true
       }
@@ -30,51 +32,86 @@ module.exports = function (path = '', sidebar) {
   logger.error(`${cwdPath} directory does not exist.`)
 }
 
-function genSidebar(cwdPath, sidebarPath) {
-  let tree = ''
-  let lastPath = ''
-  let nodeName = ''
-  getDirFiles(cwdPath, function (pathname) {
-    path.relative(pathname, cwdPath)
-    pathname = pathname.replace(cwdPath + '/', '')
-    let filename = path.basename(pathname, '.md')
-    let splitPath = pathname.split(path.sep)
-
-    if (ignoreFiles.indexOf(filename) === -1) {
-      nodeName = '- [' + filename + '](' + pathname + ')' + os.EOL
+function generateSidebar(cwdPath) {
+  return generateSidebarOfDirectory(cwdPath, cwdPath, 0)
+}
+
+/**
+ * @returns a list of string
+ */
+function generateSidebarOfDirectory(baseDirectory, currentDirectory, indentCount) {
+  let lines = []
+  // Current directory
+  const contentOfCurrentDirectory = generateSidebarContentOfDirectory(currentDirectory, indentCount)
+  console.log(contentOfCurrentDirectory)
+  lines.push(contentOfCurrentDirectory)
+
+  // Get all directories
+  const subDirectories = listDirectory(currentDirectory)
+  for (const subDirectory of subDirectories) {
+    const subLines = generateSidebarOfDirectory(baseDirectory, subDirectory, indentCount + 1)
+    for (const subLine of subLines) {
+      lines.push(subLine)
     }
+  }
 
-    if (splitPath.length > 1) {
-      if (splitPath[0] !== lastPath) {
-        lastPath = splitPath[0]
-        tree += os.EOL + '- ' + splitPath[0] + os.EOL
-      }
+  // Get all files under currentDirectory
+  const mdFilePaths = listMdFilePaths(currentDirectory)
+  for (const mdFilePath of mdFilePaths) {
+    const mdFilePathLink = generateSidebarLinkOfFile(baseDirectory, mdFilePath, indentCount + 1)
+    console.log(mdFilePathLink)
+    lines.push(mdFilePathLink)
+  }
 
-      tree += '  ' + nodeName
-    } else {
-      if (lastPath !== '') {
-        lastPath = ''
-        tree += os.EOL
+  return lines
+}
+
+function listDirectory(directory) {
+  return fs.readdirSync(directory)
+    .map(relativePath => path.join(directory, relativePath))
+    .filter(path => fs.statSync(path).isDirectory())
+}
+
+function listMdFilePaths(directory) {
+  return fs.readdirSync(directory)
+    .map(relativePath => path.join(directory, relativePath))
+    .filter(pathname => !fs.statSync(pathname).isDirectory() && path.extname(pathname) === '.md')
+    .filter(pathname => {
+      for (const ignoreFile of ignoreFiles) {
+        if (pathname.includes(ignoreFile)) {
+          return false
+        }
       }
 
-      tree += nodeName
-    }
-  })
-  fs.writeFile(sidebarPath, tree, 'utf8', err => {
-    if (err) {
-      logger.error(`Couldn't generate the sidebar file, error: ${err.message}`)
-    }
-  })
+      return true
+    })
 }
 
-function getDirFiles(dir, callback) {
-  fs.readdirSync(dir).forEach(function (file) {
-    let pathname = path.join(dir, file)
+function generateSidebarContentOfDirectory(currentDirectory, indentCount) {
+  const directoryName = path.basename(path.resolve(currentDirectory))
+  return generateIndents(indentCount) + '- ' + directoryName
+}
 
-    if (fs.statSync(pathname).isDirectory()) {
-      getDirFiles(pathname, callback)
-    } else if (path.extname(file) === '.md') {
-      callback(pathname)
-    }
-  })
+function generateSidebarLinkOfFile(baseDirectory, filePath, indentCount) {
+  return generateIndents(indentCount) + '- ' + generateLinkOfFile(baseDirectory, filePath)
+}
+
+function generateIndents(indentCount) {
+  return indent.repeat(indentCount)
+}
+
+function generateRelativePath(baseDirectory, fullPath) {
+  return path.relative(baseDirectory, fullPath)
+}
+
+function generateLinkOfFile(baseDirectory, filePath) {
+  const name = path.basename(filePath, '.md')
+  const relativePath = generateRelativePath(baseDirectory, filePath)
+  const relativePathNormalize = relativePath.split(path.sep).join('/')
+  return ''.concat('[', name, ']', '(', relativePathNormalize, ')')
+}
+
+function writeSidebar(lines, sidebarPath) {
+  const content = lines.join(os.EOL)
+  fs.writeFileSync(sidebarPath, content, 'utf8')
 }