#box2{ margin-left:50px; float:left; background:#f60; width:200px; display:inline ;}
<div class="wrap"> <div id="box2">这是个拥有正确margin-left的元素,解决的办法就是,使浮动效果消失,这里采用了display:inline;原理可参阅on having layout。</div> </div>