在UIbutton中有是三个EdgeInsets的设置：ContentEdgeInsets、titleEdgeInsets、imageEdgeInsets
left.titleEdgeInsets = UIEdgeInsetsMake(3, -25, 0, 0);
left.imageEdgeInsets = UIEdgeInsetsMake(0, -30, 0, 0);
具体左边根据需求自己调
原文：http://www.cnblogs.com/anyezhuixing/p/4128978.html