diff --git a/DSView/pv/config/appconfig.cpp b/DSView/pv/config/appconfig.cpp
index 2cabb2b4..60263498 100644
--- a/DSView/pv/config/appconfig.cpp
+++ b/DSView/pv/config/appconfig.cpp
@@ -123,13 +123,23 @@ static void _loadApp(AppOptions &o, QSettings &st)
     getFiled("swapBackBufferAlways", st, o.swapBackBufferAlways, false);
     getFiled("fontSize", st, o.fontSize, 9.0);
     getFiled("autoScrollLatestData", st, o.autoScrollLatestData, true);
+    getFiled("version", st, o.version, 1);
 
     o.warnofMultiTrig = true;
 
     QString fmt;
     getFiled("protocalFormats", st, fmt, "");
     if (fmt != ""){
-         StringToFormatArray(fmt, o.m_protocolFormats);
+        StringToFormatArray(fmt, o.m_protocolFormats);
+    }
+
+    float minSize = 0;
+    float maxSize = 0;
+    AppConfig::GetFontSizeRange(&minSize, &maxSize);
+
+    if (o.version == 1 || o.fontSize < minSize || o.fontSize > maxSize)
+    {
+        o.fontSize = (maxSize + minSize) / 2;
     }
    
     st.endGroup();
@@ -150,6 +160,7 @@ static void _saveApp(AppOptions &o, QSettings &st)
     setFiled("swapBackBufferAlways", st, o.swapBackBufferAlways);
     setFiled("fontSize", st, o.fontSize);
     setFiled("autoScrollLatestData", st, o.autoScrollLatestData);
+    setFiled("version", st, APP_CONFIG_VERSION);
 
     QString fmt =  FormatArrayToString(o.m_protocolFormats);
     setFiled("protocalFormats", st, fmt);
@@ -392,6 +403,28 @@ std::string AppConfig::GetProtocolFormat(const std::string &protocolName)
     return "";
 }
 
+void AppConfig::GetFontSizeRange(float *minSize, float *maxSize)
+{
+    assert(minSize);
+    assert(maxSize);
+
+#ifdef _WIN32
+        *minSize = 7;
+        *maxSize = 12;
+#endif
+
+#ifdef Q_OS_LINUX
+        *minSize = 8;
+        *maxSize = 14;
+#endif
+
+#ifdef Q_OS_DARWIN
+        *minSize = 9;
+        *maxSize = 15;
+#endif
+}
+
+
 //-------------api
 QString GetIconPath()
 {   
@@ -493,4 +526,4 @@ QString GetProfileDir()
     #else
     return QStandardPaths::writableLocation(QStandardPaths::DataLocation);
     #endif
-}
+}
\ No newline at end of file
diff --git a/DSView/pv/config/appconfig.h b/DSView/pv/config/appconfig.h
index aba12640..ae5da985 100644
--- a/DSView/pv/config/appconfig.h
+++ b/DSView/pv/config/appconfig.h
@@ -53,8 +53,11 @@ public:
 };
 
 
+#define APP_CONFIG_VERSION  3
+
 struct AppOptions
 {   
+    bool  version;
     bool  quickScroll;
     bool  warnofMultiTrig;
     bool  originalData;
@@ -149,6 +152,8 @@ public:
     return frameOptions.language == LAN_CN;
   }
 
+  static void GetFontSizeRange(float *minSize, float *maxSize);
+
 public:
   AppOptions    appOptions;
   UserHistory   userHistory;
diff --git a/DSView/pv/dialogs/applicationpardlg.cpp b/DSView/pv/dialogs/applicationpardlg.cpp
index fb0a24cb..4d429061 100644
--- a/DSView/pv/dialogs/applicationpardlg.cpp
+++ b/DSView/pv/dialogs/applicationpardlg.cpp
@@ -87,7 +87,12 @@ void ApplicationParamDlg::bind_font_size_list(QComboBox *box, float size)
 {   
     int selDex = -1;
 
-    for(int i=7; i<=12; i++)
+    float minSize = 0;
+    float maxSize = 0;
+
+    AppConfig::GetFontSizeRange(&minSize, &maxSize);
+
+    for(int i=minSize; i<=maxSize; i++)
     {
         box->addItem(QString::number(i));
         if (i == size){