diff --git a/cocos/2d/CCFontAtlasCache.cpp b/cocos/2d/CCFontAtlasCache.cpp
index 7881414770..d27a58bf2e 100644
--- a/cocos/2d/CCFontAtlasCache.cpp
+++ b/cocos/2d/CCFontAtlasCache.cpp
@@ -34,6 +34,7 @@
 NS_CC_BEGIN
 
 std::unordered_map<std::string, FontAtlas *> FontAtlasCache::_atlasMap;
+#define ATLAS_MAP_KEY_BUFFER 255
 
 void FontAtlasCache::purgeCachedData()
 {
@@ -53,11 +54,13 @@ FontAtlas* FontAtlasCache::getFontAtlasTTF(const _ttfConfig* config)
         useDistanceField = false;
     }
 
-    char tmp[300];
+    char tmp[ATLAS_MAP_KEY_BUFFER];
     if (useDistanceField) {
-        sprintf(tmp, "%s distance field %f %d",config->fontFilePath.c_str(), config->fontSize, config->outlineSize);
+        snprintf(tmp, ATLAS_MAP_KEY_BUFFER, "df %.2f %d %s", config->fontSize, config->outlineSize,
+                 config->fontFilePath.c_str());
     } else {
-        sprintf(tmp, "%s %f %d",config->fontFilePath.c_str(), config->fontSize, config->outlineSize);
+        snprintf(tmp, ATLAS_MAP_KEY_BUFFER, "%.2f %d %s", config->fontSize, config->outlineSize,
+                 config->fontFilePath.c_str());
     }
     std::string atlasName = tmp;
 
@@ -88,8 +91,8 @@ FontAtlas* FontAtlasCache::getFontAtlasTTF(const _ttfConfig* config)
 
 FontAtlas* FontAtlasCache::getFontAtlasFNT(const std::string& fontFileName, const Vec2& imageOffset /* = Vec2::ZERO */)
 {
-    char tmp[255];
-    sprintf(tmp, "%s %f %f", fontFileName.c_str(), imageOffset.x, imageOffset.y);
+    char tmp[ATLAS_MAP_KEY_BUFFER];
+    snprintf(tmp, ATLAS_MAP_KEY_BUFFER, "%.2f %.2f %s", imageOffset.x, imageOffset.y, fontFileName.c_str());
     std::string atlasName = tmp;
     
     auto it = _atlasMap.find(atlasName);
@@ -176,8 +179,8 @@ FontAtlas* FontAtlasCache::getFontAtlasCharMap(Texture2D* texture, int itemWidth
 
 FontAtlas* FontAtlasCache::getFontAtlasCharMap(const std::string& charMapFile, int itemWidth, int itemHeight, int startCharMap)
 {
-    char tmp[255];
-    snprintf(tmp,250,"name:%s_%d_%d_%d",charMapFile.c_str(),itemWidth,itemHeight,startCharMap);
+    char tmp[ATLAS_MAP_KEY_BUFFER];
+    snprintf(tmp, ATLAS_MAP_KEY_BUFFER, "%d %d %d %s", itemWidth, itemHeight, startCharMap, charMapFile.c_str());
     std::string atlasName = tmp;
 
     auto it = _atlasMap.find(atlasName);
@@ -229,8 +232,8 @@ bool FontAtlasCache::releaseFontAtlas(FontAtlas *atlas)
 
 void FontAtlasCache::reloadFontAtlasFNT(const std::string& fontFileName, const Vec2& imageOffset/* = Vec2::ZERO*/)
 {
-    char tmp[255];
-    sprintf(tmp, "%s %f %f", fontFileName.c_str(), imageOffset.x, imageOffset.y);
+    char tmp[ATLAS_MAP_KEY_BUFFER];
+    snprintf(tmp, ATLAS_MAP_KEY_BUFFER, "%.2f %.2f %s", imageOffset.x, imageOffset.y, fontFileName.c_str());
     std::string atlasName = tmp;
     
     auto it = _atlasMap.find(atlasName);