diff --git a/lib/cov_command.js b/lib/cov_command.js
index b19afc9e..ea2118f6 100644
--- a/lib/cov_command.js
+++ b/lib/cov_command.js
@@ -3,7 +3,6 @@
 const path = require('path');
 const mkdirp = require('mkdirp');
 const rimraf = require('rimraf');
-const sleep = require('ko-sleep');
 const Command = require('./command');
 
 class CovCommand extends Command {
@@ -44,11 +43,6 @@ class CovCommand extends Command {
     yield this.helper.forkNode(covFile, covArgs, opt);
     rimraf.sync(process.env.TMPDIR);
 
-    // wait 5 second for Windows
-    if (process.platform === 'win32') {
-      yield sleep(5000);
-    }
-
     // create coverage report
     const reportArgs = this.getReportArgs(coverageDir);
     yield this.helper.forkNode(covFile, reportArgs, opt);
diff --git a/lib/program.js b/lib/program.js
index 8b289ec7..4e3b9104 100644
--- a/lib/program.js
+++ b/lib/program.js
@@ -10,7 +10,11 @@ class Program extends BaseProgram {
     this.addCommand('dev', path.join(__dirname, 'dev_command.js'));
     this.addCommand('debug', path.join(__dirname, 'debug_command.js'));
     this.addCommand('test', path.join(__dirname, 'test_command.js'));
-    this.addCommand('cov', path.join(__dirname, 'cov_command.js'));
+    if (process.platform === 'win32') {
+      this.addCommand('cov', path.join(__dirname, 'test_command.js'));
+    } else {
+      this.addCommand('cov', path.join(__dirname, 'cov_command.js'));
+    }
   }
 }
 
diff --git a/package.json b/package.json
index bbc15e99..dbb10661 100644
--- a/package.json
+++ b/package.json
@@ -15,7 +15,6 @@
     "egg-utils": "^1.0.0",
     "glob": "^7.1.1",
     "istanbul": "^0.4.0",
-    "ko-sleep": "^1.0.2",
     "mkdirp": "^0.5.1",
     "mocha": "^3.0.0",
     "rimraf": "^2.5.4",