diff --git a/packages/SystemUI/res/values/dimens.xml b/packages/SystemUI/res/values/dimens.xml
index 9d37acceefa9c..784814d5ca381 100644
--- a/packages/SystemUI/res/values/dimens.xml
+++ b/packages/SystemUI/res/values/dimens.xml
@@ -1338,6 +1338,7 @@
     <dimen name="magnifier_up_down_controls_height">40dp</dimen>
     <!-- The extra padding to show the whole outer border -->
     <dimen name="magnifier_drag_handle_padding">3dp</dimen>
+    <dimen name="magnification_max_frame_size">300dp</dimen>
 
     <!-- Home Controls -->
     <dimen name="controls_header_side_margin">4dp</dimen>
diff --git a/packages/SystemUI/src/com/android/systemui/accessibility/WindowMagnificationController.java b/packages/SystemUI/src/com/android/systemui/accessibility/WindowMagnificationController.java
index a51e3fcfd50b7..0893e895b102c 100644
--- a/packages/SystemUI/src/com/android/systemui/accessibility/WindowMagnificationController.java
+++ b/packages/SystemUI/src/com/android/systemui/accessibility/WindowMagnificationController.java
@@ -499,9 +499,12 @@ class WindowMagnificationController implements View.OnTouchListener, SurfaceHold
     }
 
     private void setMagnificationFrameWith(Rect windowBounds, int centerX, int centerY) {
-        // Sets the initial frame area for the mirror and places it in the center of the display.
-        final int initSize = Math.min(windowBounds.width(), windowBounds.height()) / 2
-                + 2 * mMirrorSurfaceMargin;
+        // Sets the initial frame area for the mirror and place it to the given center on the
+        // display.
+        int initSize = Math.min(windowBounds.width(), windowBounds.height()) / 2;
+        initSize = Math.min(mResources.getDimensionPixelSize(R.dimen.magnification_max_frame_size),
+                initSize);
+        initSize += 2 * mMirrorSurfaceMargin;
         final int initX = centerX - initSize / 2;
         final int initY = centerY - initSize / 2;
         mMagnificationFrame.set(initX, initY, initX + initSize, initY + initSize);
diff --git a/packages/SystemUI/tests/src/com/android/systemui/accessibility/WindowMagnificationControllerTest.java b/packages/SystemUI/tests/src/com/android/systemui/accessibility/WindowMagnificationControllerTest.java
index 323b5fe4636ff..3291a7c24867c 100644
--- a/packages/SystemUI/tests/src/com/android/systemui/accessibility/WindowMagnificationControllerTest.java
+++ b/packages/SystemUI/tests/src/com/android/systemui/accessibility/WindowMagnificationControllerTest.java
@@ -170,6 +170,29 @@ public class WindowMagnificationControllerTest extends SysuiTestCase {
         assertFalse(rects.isEmpty());
     }
 
+    @Test
+    public void enableWindowMagnification_LargeScreen_windowSizeIsConstrained() {
+        final int screenSize = mContext.getResources().getDimensionPixelSize(
+                R.dimen.magnification_max_frame_size) * 10;
+        mWindowManager.setWindowBounds(new Rect(0, 0, screenSize, screenSize));
+        //We need to initialize new one because the window size is determined when initialization.
+        final WindowMagnificationController controller = new WindowMagnificationController(mContext,
+                mHandler, mSfVsyncFrameProvider,
+                mMirrorWindowControl, mTransaction, mWindowMagnifierCallback, mSysUiState);
+
+        mInstrumentation.runOnMainSync(() -> {
+            controller.enableWindowMagnification(Float.NaN, Float.NaN,
+                    Float.NaN);
+        });
+
+        final int halfScreenSize = screenSize / 2;
+        WindowManager.LayoutParams params = mWindowManager.getLayoutParamsFromAttachedView();
+        // The frame size should be the half of smaller value of window height/width unless it
+        //exceed the max frame size.
+        assertTrue(params.width < halfScreenSize);
+        assertTrue(params.height < halfScreenSize);
+    }
+
     @Test
     public void deleteWindowMagnification_destroyControl() {
         mInstrumentation.runOnMainSync(() -> {
@@ -318,6 +341,27 @@ public class WindowMagnificationControllerTest extends SysuiTestCase {
                 mWindowMagnificationController.getCenterY() / testWindowBounds.height(),
                 0);
     }
+    @Test
+    public void screenSizeIsChangedToLarge_enabled_windowSizeIsConstrained() {
+        mInstrumentation.runOnMainSync(() -> {
+            mWindowMagnificationController.enableWindowMagnification(Float.NaN, Float.NaN,
+                    Float.NaN);
+        });
+        final int screenSize = mContext.getResources().getDimensionPixelSize(
+                R.dimen.magnification_max_frame_size) * 10;
+        mWindowManager.setWindowBounds(new Rect(0, 0, screenSize, screenSize));
+
+        mInstrumentation.runOnMainSync(() -> {
+            mWindowMagnificationController.onConfigurationChanged(ActivityInfo.CONFIG_SCREEN_SIZE);
+        });
+
+        final int halfScreenSize = screenSize / 2;
+        WindowManager.LayoutParams params = mWindowManager.getLayoutParamsFromAttachedView();
+        // The frame size should be the half of smaller value of window height/width unless it
+        //exceed the max frame size.
+        assertTrue(params.width < halfScreenSize);
+        assertTrue(params.height < halfScreenSize);
+    }
 
     @Test
     public void onDensityChanged_enabled_updateDimensionsAndResetWindowMagnification() {