diff --git a/lib/command/build.js b/lib/command/build.js
index 68d7235a..739522ca 100644
--- a/lib/command/build.js
+++ b/lib/command/build.js
@@ -30,18 +30,20 @@ build.run = function(options, callback) {
   var tasks = options.install
     ? [
       'simplely_read_cortex_json',
+      'prepare_build_type',
       'run_preinstall_script',
       'run_prebuild_script',
       'build_process',
       'server_link'
     ] : [
       'read_cortex_json',
+      'clean_cortex_json',
+      'prepare_build_type',
       'run_preinstall_script',
       'run_prebuild_script',
       // #478
       // `cortex.main` and many other files might have not been generated before `cortex.scripts`
       // so, we clean cortex_json
-      'clean_cortex_json',
       'build_process',
       'server_link',
       'run_postbuild_script',
@@ -52,6 +54,29 @@ build.run = function(options, callback) {
   }, callback);
 };
 
+build.prepare_build_type = function(options, callback){
+  var pkg = options.pkg;
+  var entries = pkg.entries;
+  var csses = pkg.css;
+
+  function hasFile(list){
+    return list.map(function(rel){
+      return node_path.join(options.cwd, rel);
+    }).indexOf(options.file) > -1;
+  }
+
+  if(hasFile(entries)){
+    options.build_type = 'js';
+  }else if(hasFile(csses)){
+    options.build_type = 'css';
+  }else if(isDir()){
+    options.build_type = 'dir';
+  }else{
+    options.build_type = 'full';
+  }
+
+  callback();
+};
 
 build.simplely_read_cortex_json = function (options, callback) {
   // If install from cache, cortex.json will be enhanced json.
@@ -134,6 +159,10 @@ build.run_prebuild_script = function(options, callback) {
   if (!options.prebuild) {
     return callback(null);
   }
+
+  if(options.build_type != 'full'){
+    return callback(null);
+  }
   this.run_script('prebuild', options, callback);
 };
 
@@ -442,6 +471,11 @@ build.build_modules = function(options, callback) {
   var cwd = options.cwd;
   var to = options.to;
   var self = this;
+
+  if(options.build_type == 'js'){
+    entries = [node_path.relative(options.cwd, options.file)];
+  }
+  
   async.eachSeries(entries, function (entry, done) {
     var from = node_path.join(cwd, entry);
     builder({
@@ -480,15 +514,28 @@ build.build_modules = function(options, callback) {
   }, callback);
 };
 
+build._is_type = function(build_type, type){
+  // build_type is from step prepare filelist
+  return build_type == 'full' || build_type == type;
+};
 
 build.copy_csses = function (options, callback) {
   var css = options.pkg.css;
   if (!css) {
     return callback(null);
   }
+
+  if(!this._is_type(options.build_type, 'css')){
+    return callback(null);
+  }
+
   var self = this;
   var to = options.to;
 
+  if(options.build_type == 'css'){
+    css = [node_path.relative(options.cwd, options.file)];
+  }
+
   async.eachSeries(css, function (path, done) {
     var from = options.cwd;
     var css_path = node_path.join(from, path);
diff --git a/lib/command/watch.js b/lib/command/watch.js
index da473136..d92152a9 100644
--- a/lib/command/watch.js
+++ b/lib/command/watch.js
@@ -36,6 +36,7 @@ watch._createWatcher = function (options) {
     // only emitted on master watcher process
   })
   .on('all', function(event, filepath) {
+    options.file = filepath;
     var dir = node_path.dirname(filepath);
     // cortex commander will santitize filepath to the right root directory of the repo
     self._rebuild(options, dir);
@@ -210,7 +211,8 @@ watch._rebuild = function(options, cwd, init) {
       'build',
       // Use --force to prevent grunt task interrupt the current process
       '--force',
-      '--cwd', cwd
+      '--cwd', cwd,
+      '--file', options.file
     ];
 
     var prerelease = options.prerelease;
diff --git a/lib/option/build.js b/lib/option/build.js
index 1609c70c..6a268151 100644
--- a/lib/option/build.js
+++ b/lib/option/build.js
@@ -18,6 +18,11 @@ exports.options = {
     default: false
   },
 
+  file: {
+    type: node_path,
+    default: ''
+  },
+
   prebuild: {
     enumerable: false,
     type: Boolean,