diff --git a/lib/screenutil.dart b/lib/screenutil.dart
index b9e2061..59e84b0 100644
--- a/lib/screenutil.dart
+++ b/lib/screenutil.dart
@@ -35,7 +35,9 @@ class ScreenUtil {
   }
 
   static void init(
-    BoxConstraints constraints, {
+    BoxConstraints constraints, 
+    Orientation orientation,
+    {
     Size designSize = defaultSize,
     bool allowFontScaling = false,
   }) {
@@ -43,8 +45,13 @@ class ScreenUtil {
     _instance
       ..uiSize = designSize
       ..allowFontScaling = allowFontScaling;
-    _screenWidth = constraints.maxWidth;
+    if(orientation == Orientation.potrait){
+      _screenWidth = constraints.maxWidth;
     _screenHeight = constraints.maxHeight;
+    }else{
+      _screenWidth = constraints.maxHeight;
+    _screenHeight = constraints.maxWidth;
+    }
 
     var window = WidgetsBinding.instance?.window ?? ui.window;
     _pixelRatio = window.devicePixelRatio;
diff --git a/lib/screenutil_init.dart b/lib/screenutil_init.dart
index 50a0631..666b639 100644
--- a/lib/screenutil_init.dart
+++ b/lib/screenutil_init.dart
@@ -22,16 +22,21 @@ class ScreenUtilInit extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return LayoutBuilder(
-      // ignore: missing_return
       builder: (_, BoxConstraints constraints) {
-        if (constraints.maxWidth != 0) {
-          ScreenUtil.init(
-            constraints,
-            designSize: designSize,
-            allowFontScaling: allowFontScaling,
-          );
-        }
-        return builder();
+        return OrientationBuilder(
+          builder: (_, Orientation orientation) {
+            // ignore: missing_return
+            if (constraints.maxWidth != 0) {
+              ScreenUtil.init(
+                constraints,
+                orientation,
+                designSize: designSize,
+                allowFontScaling: allowFontScaling,
+              );
+            }
+            return builder();
+          },
+        );
       },
     );
   }