diff --git a/packages/less/test/browser/generator/runner.config.js b/packages/less/test/browser/generator/runner.config.js
index 8eba09831..395987f22 100644
--- a/packages/less/test/browser/generator/runner.config.js
+++ b/packages/less/test/browser/generator/runner.config.js
@@ -1,14 +1,15 @@
 var path = require('path');
-var resolve = require('resolve')
+var resolve = require('resolve');
+var { forceCovertToBrowserPath } = require('./utils');
 
 /** Root of repo */
-var testFolder = path.posix.normalize(path.dirname(resolve.sync('@less/test-data')));
-var lessFolder = path.posix.normalize(path.join(testFolder, 'less'));
-var localTests = path.posix.normalize(path.resolve(__dirname, '..'));
+var testFolder = forceCovertToBrowserPath(path.dirname(resolve.sync('@less/test-data')));
+var lessFolder = forceCovertToBrowserPath(path.join(testFolder, 'less'));
+var localTests = forceCovertToBrowserPath(path.resolve(__dirname, '..'));
 
 console.log(
-    `normalize: `, path.normalize(path.dirname(resolve.sync('@less/test-data'))),
-    `posix normalize: `, path.posix.normalize(path.dirname(resolve.sync('@less/test-data')))
+    `normal: `, path.dirname(resolve.sync('@less/test-data')),
+    `forceCovertToBrowserPath: `, forceCovertToBrowserPath(path.dirname(resolve.sync('@less/test-data')))
 )
 
 module.exports = {
diff --git a/packages/less/test/browser/generator/utils.js b/packages/less/test/browser/generator/utils.js
new file mode 100644
index 000000000..a2041f1f2
--- /dev/null
+++ b/packages/less/test/browser/generator/utils.js
@@ -0,0 +1,14 @@
+/**
+ * utils for covert browser paths,
+ * fix https://github.com/less/less.js/pull/4213 
+ * 
+ * @param {string} path 
+ * @returns {string}
+ */
+function forceCovertToBrowserPath (path) {
+    return (path || '').replace(/\\/g, '/');
+}
+
+module.exports = {
+    forceCovertToBrowserPath
+}