diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index 539bc00d34..e0a0a77819 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -9,6 +9,7 @@ Yii Framework 2 Change Log
 - Enh #6247: Logger and error handler are now using slightly less memory (stepanselyuk, samdark)
 - Enh #6434: Added `yii\behaviors\SluggableBehavior::immutable` to support keeping the generated slug unchanged (trntv)
 - Enh #6467: `ActiveForm` will scroll to the nearest visible element when the first error input is hidden (newartix)
+- Enh #6488: Support changing `yii\base\Theme::basePath` during runtime (qiangxue)
 - Chg #6427: In case of invalid route web application now throws exception with "Page not found" instead of "Invalid Route" (cebe, samdark)
 
 2.0.1 December 07, 2014
diff --git a/framework/base/Theme.php b/framework/base/Theme.php
index b89877bad3..d079812d5c 100644
--- a/framework/base/Theme.php
+++ b/framework/base/Theme.php
@@ -73,29 +73,12 @@ class Theme extends Component
 {
     /**
      * @var array the mapping between view directories and their corresponding themed versions.
-     * If not set, it will be initialized as a mapping from [[Application::basePath]] to [[basePath]].
      * This property is used by [[applyTo()]] when a view is trying to apply the theme.
      * Path aliases can be used when specifying directories.
+     * If this property is empty or not set, a mapping [[Application::basePath]] to [[basePath]] will be used.
      */
     public $pathMap;
 
-
-    /**
-     * Initializes the theme.
-     * @throws InvalidConfigException if [[basePath]] is not set.
-     */
-    public function init()
-    {
-        parent::init();
-
-        if (empty($this->pathMap)) {
-            if (($basePath = $this->getBasePath()) === null) {
-                throw new InvalidConfigException('The "basePath" property must be set.');
-            }
-            $this->pathMap = [Yii::$app->getBasePath() => [$basePath]];
-        }
-    }
-
     private $_baseUrl;
 
     /**
@@ -142,11 +125,21 @@ class Theme extends Component
      * If there is no corresponding themed file, the original file will be returned.
      * @param string $path the file to be themed
      * @return string the themed file, or the original file if the themed version is not available.
+     * @throws InvalidConfigException if [[basePath]] is not set
      */
     public function applyTo($path)
     {
+        $pathMap = $this->pathMap;
+        if (empty($pathMap)) {
+            if (($basePath = $this->getBasePath()) === null) {
+                throw new InvalidConfigException('The "basePath" property must be set.');
+            }
+            $pathMap = [Yii::$app->getBasePath() => [$basePath]];
+        }
+
         $path = FileHelper::normalizePath($path);
-        foreach ($this->pathMap as $from => $tos) {
+
+        foreach ($pathMap as $from => $tos) {
             $from = FileHelper::normalizePath(Yii::getAlias($from)) . DIRECTORY_SEPARATOR;
             if (strpos($path, $from) === 0) {
                 $n = strlen($from);