diff --git a/framework/yii/caching/FileCache.php b/framework/yii/caching/FileCache.php
index 0c6d119..1dbcb09 100644
--- a/framework/yii/caching/FileCache.php
+++ b/framework/yii/caching/FileCache.php
@@ -25,8 +25,9 @@ class FileCache extends Cache
 {
 	/**
 	 * @var string the directory to store cache files. You may use path alias here.
+	 * If not set, it will use the "cache" subdirectory under the application runtime path.
 	 */
-	public $cachePath = '@app/runtime/cache';
+	public $cachePath;
 	/**
 	 * @var string cache file suffix. Defaults to '.bin'.
 	 */
@@ -51,7 +52,11 @@ class FileCache extends Cache
 	public function init()
 	{
 		parent::init();
-		$this->cachePath = Yii::getAlias($this->cachePath);
+		if ($this->cachePath === null) {
+			$this->cachePath = Yii::$app->getRuntimePath() . DIRECTORY_SEPARATOR . 'cache';
+		} else {
+			$this->cachePath = Yii::getAlias($this->cachePath);
+		}
 		if (!is_dir($this->cachePath)) {
 			mkdir($this->cachePath, 0777, true);
 		}