IOS 7 以上系统导航栏:

[[UINavigationBar appearance] setTintColor:[UIColor whiteColor]]; // 返回按钮颜色
[UINavigationBar appearance].barTintColor = YK_BUTTON_COLOR; //背景颜色
[[UINavigationBar appearance] setTitleTextAttributes:[NSDictionary dictionaryWithObjectsAndKeys:[UIColor whiteColor],NSForegroundColorAttributeName,[UIFont boldSystemFontOfSize:17],NSFontAttributeName, nil]]; //标题title属性

  

IOS6以上自定义导航栏:

 /*自定义标题*/    
UILabel *vTitleLable = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 200, 21)];
    vTitleLable.font = [UIFont boldSystemFontOfSize:17];
    vTitleLable.textColor = [UIColor whiteColor];
    vTitleLable.textAlignment = NSTextAlignmentCenter;
    vTitleLable.backgroundColor = [UIColor clearColor];
    vTitleLable.text = _titleStr;
    [self.navigationItem setTitleView:vTitleLable];

  /*自定义返回按钮*/
  UIBarButtonItem *vLeftButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(backButtonClicked:)];
    self.navigationItem.leftBarButtonItem = vLeftButtonItem; 
   [vLeftButtonItem release];