div+css怎样才能<ul><li>靠左边对齐,为什么距左边有很大的间距,该如何处理

div+css怎样才能<ul><li>靠左边对齐,为什么距左边有很大的间距
<div id="kechen">
<ul>
<li><img src="images/niao.gif" border="0"><a href="#">aaa</a></li>
<li><img src="images/niao.gif" border="0"><a href="#">aaa</a></li>
<li><img src="images/niao.gif" border="0"><a href="#">aaa</a></li>
<li><img src="images/niao.gif" border="0"><a href="#">aaa</a></li>
</ul>
</div>

#kechen { padding:0px; list-style-type:none; }
#kechen li{height:30px; text-align:left; margin:0px; padding:0px; list-style-type:none;}
#kechen img {padding-right:5px;}

------解决方案--------------------
margin:0;
padding:0
------解决方案--------------------

CSS code

#kechen { padding:0px; list-style-type:none; float:left; } 
#kechen ul{ padding:0px; margin:0px;}
#kechen li{height:30px; text-align:left; margin:0px; padding:0px; list-style-type:none;} 
#kechen img { padding:0px;}