.k3 .ttx{display:none;}
.k3:hover .ttx{
display:block;
position: absolute; left: -118px;
padding:13px 8px;
top: 20px;
background:#fff;
border:1px solid #e4e4e4;
border-right:none;
}

<div class="k1">
  <div style="background-color:#43adeb; color:#fff;"> 手机微信<br />
    扫码关注 </div>
  <div class="k0"> <img src="/cgy/img/wx.jpg"> </div>
  <div class="k2"><a href="http://wpa.qq.com/msgrd?v=3&uin={dede:global.cfg_qq/}&site=qq&menu=yes" target="_blank"><img src="/cgy/img/k1.jpg"></a> 在线客服 </div>
  <div class="k2 k3"> <img src="/cgy/img/k2.jpg"> 客服中心<span class="ttx">{dede:global.cfg_dianhua/}</span> </div>
  <div style="background-color:#43adeb; color:#fff; padding:8px 0;"> 100%正品 </div>
</div>