diff --git a/cocos/2d/CCLabel.cpp b/cocos/2d/CCLabel.cpp
index 39aaa8860c..980ed7a8c2 100644
--- a/cocos/2d/CCLabel.cpp
+++ b/cocos/2d/CCLabel.cpp
@@ -1226,6 +1226,15 @@ void Label::computeStringNumLines()
     _currNumLines = quantityOfLines;
 }
 
+int Label::getStringNumLines() const {
+    if (_contentDirty)
+    {
+        const_cast<Label*>(this)->updateContent();
+    }
+
+    return _currNumLines;
+}
+
 int Label::getStringLength() const
 {
     return static_cast<int>(_currentUTF16String.length());
diff --git a/cocos/2d/CCLabel.h b/cocos/2d/CCLabel.h
index c41f5c0da8..59e9288ab6 100644
--- a/cocos/2d/CCLabel.h
+++ b/cocos/2d/CCLabel.h
@@ -235,7 +235,7 @@ public:
     float getAdditionalKerning() const;
 
     // string related stuff
-    int getStringNumLines() const { return _currNumLines;}
+    int getStringNumLines() const;
     int getStringLength() const;
 
     FontAtlas* getFontAtlas() { return _fontAtlas; }