CSS

 .select { margin: 0; padding: 0; border:1px solid #cccccc; float: left; display: inline; }
 .select div { border:1px solid #f9f9f9; float: left; }
 .select>div { overflow: hidden; }
 * html .select div select { display:block; float: left; margin: -2px; }
 .select div>select { display:block; float:none; margin: -2px; padding: 0px; }
 .select:hover { border:1px solid #666; }

HTML

<div class="select">
    <div>
        <select>
            <option>看见效果了吧</option>
            <option>看见效果了吧</option>
            <option>看见效果了吧</option>
        </select>
    </div>
    <div>

直接看演示吧
demo演示地址:http://www.w3cways.com/example?pid=239