diff --git a/GKNavigationBar.podspec b/GKNavigationBar.podspec
index a60f227..c02679f 100644
--- a/GKNavigationBar.podspec
+++ b/GKNavigationBar.podspec
@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name                    = 'GKNavigationBar'
-  s.version                 = '1.5.5'
+  s.version                 = '1.5.6'
   s.license                 = 'MIT'
   s.summary                 = '自定义导航栏--导航栏联动'
   s.homepage                = 'https://github.com/QuintGao/GKNavigationBar'
@@ -8,7 +8,6 @@ Pod::Spec.new do |s|
   s.authors                 = { '高坤' => '1094887059@qq.com' }
   s.source                  = { :git => 'https://github.com/QuintGao/GKNavigationBar.git', :tag => s.version }
   s.ios.deployment_target   = '9.0'
-  
   s.source_files            = 'GKNavigationBar/GKNavigationBar.h'
   
   s.subspec 'NavigationBar' do |ss|
diff --git a/GKNavigationBar/GestureHandle/UINavigationController+GKGestureHandle.m b/GKNavigationBar/GestureHandle/UINavigationController+GKGestureHandle.m
index 6b80041..3463e8a 100644
--- a/GKNavigationBar/GestureHandle/UINavigationController+GKGestureHandle.m
+++ b/GKNavigationBar/GestureHandle/UINavigationController+GKGestureHandle.m
@@ -143,6 +143,8 @@ - (void)propertyChangeNotification:(NSNotification *)notification {
     if ([vc isKindOfClass:[UITabBarController class]]) return;
     if (!vc.navigationController) return;
     if (vc.navigationController != self) return;
+    // 修复非导航控制器子类时出现的问题
+    if (vc.parentViewController != self) return;
     
     __block BOOL exist = NO;
     [GKGestureConfigure.shiledGuestureVCs enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
diff --git a/GKNavigationBar/NavigationBar/UIViewController+GKNavigationBar.m b/GKNavigationBar/NavigationBar/UIViewController+GKNavigationBar.m
index f549b1b..25ae4db 100644
--- a/GKNavigationBar/NavigationBar/UIViewController+GKNavigationBar.m
+++ b/GKNavigationBar/NavigationBar/UIViewController+GKNavigationBar.m
@@ -52,6 +52,10 @@ - (void)gk_viewDidLoad {
         self.gk_navItemRightSpace   = GKNavigationBarItemSpace;
         self.gk_disableFixNavItemSpace = [self checkFixNavItemSpace];
     }
+    // 如果是根控制器，取消返回按钮
+    if (self.navigationController && self.navigationController.childViewControllers.count <= 1) {
+        self.gk_navLeftBarButtonItem = nil;
+    }
     [self gk_viewDidLoad];
 }
 
@@ -554,19 +558,24 @@ - (void)setupNavBarAppearance {
 }
 
 - (void)setupNavBarFrame {
+    BOOL isNonFullScreen = NO;
+    CGFloat viewW = GK_SCREEN_WIDTH;
+    CGFloat viewH = GK_SCREEN_HEIGHT;
     // 防止在init方法中创建导航栏会提前触发viewDidLoad方法，所以做下判断
-    if (!self.isViewLoaded) return;
-    UIViewController *parentVC = self;
-    while (parentVC.parentViewController) {
-        parentVC = parentVC.parentViewController;
+    if (self.isViewLoaded) {
+        UIViewController *parentVC = self;
+        // 找到最上层的父类
+        while (parentVC.parentViewController) {
+            parentVC = parentVC.parentViewController;
+        }
+        viewW = parentVC.view.frame.size.width;
+        viewH = parentVC.view.frame.size.height;
+        if (viewW == 0 || viewH == 0) return;
+        
+        // 如果是通过present方式弹出且高度小于屏幕高度，则认为是非全屏
+        isNonFullScreen = self.presentingViewController && viewH < GK_SCREEN_HEIGHT;
     }
     
-    CGFloat viewW = parentVC.view.frame.size.width;
-    CGFloat viewH = parentVC.view.frame.size.height;
-    if (viewW == 0 || viewH == 0) return;
-    
-    BOOL isNonFullScreen = self.presentingViewController && viewH < GK_SCREEN_HEIGHT;
-    
     CGFloat navBarH = 0.0f;
     if (GK_IS_iPad) { // iPad
         if (isNonFullScreen) {
@@ -622,7 +631,10 @@ - (BOOL)navItemSpaceChangeIfNeeded {
 - (void)setBackItemImage:(UIImage *)image {
     if (!self.gk_NavBarInit) return;
     // 根控制器不作处理
-    if (self.navigationController.childViewControllers.count <= 1) return;
+    if (self.navigationController && self.navigationController.childViewControllers.count <= 1) {
+        self.gk_navLeftBarButtonItem = nil;
+        return;
+    }
     
     if (!image) {
         if (self.gk_backStyle != GKNavigationBarBackStyleNone) {
diff --git a/GKNavigationBarExample/GKNavigationBarExample/Demo/GKMainViewController.m b/GKNavigationBarExample/GKNavigationBarExample/Demo/GKMainViewController.m
index ab9148f..a7541bf 100644
--- a/GKNavigationBarExample/GKNavigationBarExample/Demo/GKMainViewController.m
+++ b/GKNavigationBarExample/GKNavigationBarExample/Demo/GKMainViewController.m
@@ -167,7 +167,11 @@ - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath
             wxVC.modalPresentationStyle = UIModalPresentationFullScreen;
             [self presentViewController:wxVC animated:YES completion:nil];
         }else if (indexPath.row == 11) {
-            UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:[GKPresentViewController new]];
+            GKPresentViewController *presentVC = [GKPresentViewController new];
+            presentVC.gk_navTitle = @"presentVC";
+            
+            UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:presentVC];
+            
             [self presentViewController:nav animated:YES completion:nil];
         }
     }
diff --git a/README.md b/README.md
index 22e9a0c..f0cf737 100644
--- a/README.md
+++ b/README.md
@@ -206,6 +206,7 @@ configure.shiledGuestureVCs = @[NSClassFromString(@"TZPhotoPickerController"), @
   <summary><font size=4>最近更新</font></summary>
 
 ```
+1.5.6 - 2021.05.18 优化导航栏返回按钮及高度处理#77，手势处理优化
 1.5.5 - 2021.05.14 修复导航栏间距失效的问题#76
 1.5.4 - 2021.05.12 修复可能提前触发viewDidLoad方法的问题
 1.5.3 - 2021.05.07 修复直接设置背景色无效的问题#71，#74，增加对非全屏的支持