<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><!--定义过渡型DOCTYPE-->
<html xmlns="http://www.w3.org/1999/xhtml" lang="gb2312"><!--定义名字空间-->
<head>
<title>二级菜单</title><!--标题栏-->
<meta http-equiv="Content-Type" content="text/htmlcharset=gb2312" /><!--定义语言编码-->
<meta http-equiv="Content-Language" content="gb2312" /><!--针对老版浏览器定义语言编码-->
<<meta name="description" content="下拉菜单,CSS,布局" /><!--简介-->
<meta content="下拉,菜单,CSS,布局" name="keywords" /><!--关键词-->
<!--CSS样式开始-->
<style type=text/css>
*{
margin:0
padding:0
border:0
}
html{
background:#bfc4c7/*背景颜色*/
}
body{
font:12px/150% '宋体'
margin:0 auto
width:770px
text-align:center
}
#menu,#nav,#footer{
clear:both
}
#nav{
padding-left:20px
text-align:left
background:#a60
}
#footer{
background:#a30
}
#logo,#banner,#mail,#left,#middle,#right{
float:left
width:180px
background:#f00
}
#logo,#banner,#mail{
height:60px
}
#banner{
width:468px
background:#f60
}
#mail{
width:122px
background:#f90
}
#left,#right{
width:200px
}
#left{
background:#093
}
#middle{
width:370px
background:#063
}
#right{
background:#033
}
/*menu部分*/
#menu{
margin:0
position:relative
width:770px!important
}
#menu ul{
list-style:none
}
#menu li {
float:left
position:relative
}
#menu ul ul {
visibility:hidden
position:absolute
left:0px
top:30px
}
#menu table{
position:absolute
left:0
top:0
}
#menu ul li:hover ul,#menu ul a:hover ul{
visibility:visible
}
#menu a{
display:block
text-align:center
text-decoration:none
width:77px
height:30px
color:#000
line-height:30px
background:#c9c9a7
}
#menu a:hover{
color:#fff
background:#b3ab79
}
#menu ul ul li {
clear:both
text-align:left
}
#menu ul ul li a{
display:block
width:77px
height:30px
background:#faeec7
color:#000
}
#menu ul ul li a:hover{
background:#dfc184
color:#000
}
</style><!--CSS样式结束-->
</head><!--网页头部结束-->
<body><!--网页主体开始-->
<div id="menu">
<ul>
<li>
<a href="">第一分类<!--[if IE 7]><!--></a><!--<![endif]--><!--[if lte IE 6]>
<table>
<tr>
<td><![endif]-->
<ul>
<li><a href="">XHTML</a></li>
<li><a href="">CSS</a></li>
<li><a href="">PHP</a></li>
<li><a href="">MySQL</a></li>
<li><a href="">Fireworks</a></li>
<li><a href="">Photoshop</a></li>
<li><a href="">Flash</a></li>
<li><a href="">Illustrator</a></li>
</ul><!--[if lte IE 6]>
</td>
</tr>
</table>
</a><![endif]-->
</li>
<li>
<a href="">第一分类<!--[if IE 7]><!--></a><!--<![endif]--><!--[if lte IE 6]>
<table>
<tr>
<td><![endif]-->
<ul>
<li><a href="">XHTML</a></li>
<li><a href="">CSS</a></li>
<li><a href="">PHP</a></li>
<li><a href="">MySQL</a></li>
<li><a href="">Fireworks</a></li>
<li><a href="">Photoshop</a></li>
<li><a href="">Flash</a></li>
<li><a href="">Illustrator</a></li>
</ul><!--[if lte IE 6]>
</td>
</tr>
</table>
</a><![endif]-->
</li>
<li>
<a href="">第一分类<!--[if IE 7]><!--></a><!--<![endif]--><!--[if lte IE 6]>
<table>
<tr>
<td><![endif]-->
<ul>
<li><a href="">XHTML</a></li>
<li><a href="">CSS</a></li>
<li><a href="">PHP</a></li>
<li><a href="">MySQL</a></li>
<li><a href="">Fireworks</a></li>
<li><a href="">Photoshop</a></li>
<li><a href="">Flash</a></li>
<li><a href="">Illustrator</a></li>
</ul><!--[if lte IE 6]>
</td>
</tr>
</table>
</a><![endif]-->
</li>
<li>
<a href="">第一分类<!--[if IE 7]><!--></a><!--<![endif]--><!--[if lte IE 6]>
<table>
<tr>
<td><![endif]-->
<ul>
<li><a href="">XHTML</a></li>
<li><a href="">CSS</a></li>
<li><a href="">PHP</a></li>
<li><a href="">MySQL</a></li>
<li><a href="">Fireworks</a></li>
<li><a href="">Photoshop</a></li>
<li><a href="">Flash</a></li>
<li><a href="">Illustrator</a></li>
</ul><!--[if lte IE 6]>
</td>
</tr>
</table>
</a><![endif]-->
</li>
<li>
<a href="">第一分类<!--[if IE 7]><!--></a><!--<![endif]--><!--[if lte IE 6]>
<table>
<tr>
<td><![endif]-->
<ul>
<li><a href="">XHTML</a></li>
<li><a href="">CSS</a></li>
<li><a href="">PHP</a></li>
<li><a href="">MySQL</a></li>
<li><a href="">Fireworks</a></li>
<li><a href="">Photoshop</a></li>
<li><a href="">Flash</a></li>
<li><a href="">Illustrator</a></li>
</ul><!--[if lte IE 6]>
</td>
</tr>
</table>
</a><![endif]-->
</li>
<li>
<a href="">第一分类<!--[if IE 7]><!--></a><!--<![endif]--><!--[if lte IE 6]>
<table>
<tr>
<td><![endif]-->
<ul>
<li><a href="">XHTML</a></li>
<li><a href="">CSS</a></li>
<li><a href="">PHP</a></li>
<li><a href="">MySQL</a></li>
<li><a href="">Fireworks</a></li>
<li><a href="">Photoshop</a></li>
<li><a href="">Flash</a></li>
<li><a href="">Illustrator</a></li>
</ul><!--[if lte IE 6]>
</td>
</tr>
</table>
</a><![endif]-->
</li>
<li>
<a href="">第一分类<!--[if IE 7]><!--></a><!--<![endif]--><!--[if lte IE 6]>
<table>
<tr>
<td><![endif]-->
<ul>
<li><a href="">XHTML</a></li>
<li><a href="">CSS</a></li>
<li><a href="">PHP</a></li>
<li><a href="">MySQL</a></li>
<li><a href="">Fireworks</a></li>
<li><a href="">Photoshop</a></li>
<li><a href="">Flash</a></li>
<li><a href="">Illustrator</a></li>
</ul><!--[if lte IE 6]>
</td>
</tr>
</table>
</a><![endif]-->
</li>
<li>
<a href="">第一分类<!--[if IE 7]><!--></a><!--<![endif]--><!--[if lte IE 6]>
<table>
<tr>
<td><![endif]-->
<ul>
<li><a href="">XHTML</a></li>
<li><a href="">CSS</a></li>
<li><a href="">PHP</a></li>
<li><a href="">MySQL</a></li>
<li><a href="">Fireworks</a></li>
<li><a href="">Photoshop</a></li>
<li><a href="">Flash</a></li>
<li><a href="">Illustrator</a></li>
</ul><!--[if lte IE 6]>
</td>
</tr>
</table>
</a><![endif]-->
</li>
<li>
<a href="">第一分类<!--[if IE 7]><!--></a><!--<![endif]--><!--[if lte IE 6]>
<table>
<tr>
<td><![endif]-->
<ul>
<li><a href="">XHTML</a></li>
<li><a href="">CSS</a></li>
<li><a href="">PHP</a></li>
<li><a href="">MySQL</a></li>
<li><a href="">Fireworks</a></li>
<li><a href="">Photoshop</a></li>
<li><a href="">Flash</a></li>
<li><a href="">Illustrator</a></li>
</ul><!--[if lte IE 6]>
</td>
</tr>
</table>
</a><![endif]-->
</li>
<li>
<a href="">第一分类<!--[if IE 7]><!--></a><!--<![endif]--><!--[if lte IE 6]>
<table>
<tr>
<td><![endif]-->
<ul>
<li><a href="">XHTML</a></li>
<li><a href="">CSS</a></li>
<li><a href="">PHP</a></li>
<li><a href="">MySQL</a></li>
<li><a href="">Fireworks</a></li>
<li><a href="">Photoshop</a></li>
<li><a href="">Flash</a></li>
<li><a href="">Illustrator</a></li>
</ul><!--[if lte IE 6]>
</td>
</tr>
</table>
</a><![endif]-->
</li>
</ul>
</div>
</body><!--网页主体结束-->
</html>
我给楼主看了一下```你要的效果没说清楚`如果想显示出下拉列表直接删掉 #menu li dd{display:none}
就可以了。如果想鼠标移动后，出现下拉列表，我没看到楼主定义这个类型，所以给楼主一个我以前写的，仅供参考。
.imcm ul,.imcm li,.imcm div,.imcm span,.imcm a{text-align:leftvertical-align:toppadding:0pxmargin:0list-style:none outside noneborder-style:nonebackground-image:noneclear:nonefloat:nonedisplay:blockposition:staticoverflow:visibleline-height:normal}
.imcm li a img{display:inlineborder-width:0px}
.imcm span{display:inline}
.imcm .imclear,.imclear{clear:bothheight:0pxvisibility:hiddenline-height:0pxfont-size:1px}.imcm .imsc{position:relative}.imcm .imsubc{position:absolutevisibility:hidden}.imcm li{list-style:nonefont-size:1pxfloat:left}.imcm ul ul li{width:100float:left !important}
.imcm a{display:blockposition:relative}
.imcm ul .imsc,.imcm ul .imsubc {z-index:10}
.imcm ul ul .imsc,.imcm ul ul .imsubc{z-index:20}
.imcm ul ul ul .imsc,.imcm ul ul ul .imsubc{z-index:30}
.imde ul li:hover .imsubc{visibility:visible}
.imde ul ul li:hover
.imsubc{visibility:visible}
.imde ul ul ul li:hover
.imsubc{visibility:visible}
.imde li:hover ul .imsubc{visibility:hidden}
.imde li:hover ul ul .imsubc{visibility:hidden}
.imde li:hover ul ul ul .imsubc{visibility:hidden}
.imcm .imea{display:blockposition:relativeleft:0pxfont-size:1pxline-height:1pxheight:0pxwidth:1pxfloat:right}
.imcm .imea span{display:blockposition:relativefont-size:1pxline-height:0px}.dvs,.dvm{border-width:0px}/*\*//*/.imcm .imea{visibility:hidden}/**/</style><!--[if IE]><style type="text/css">.imcm .imea span{position:absolute}.imcm .imclear,.imclear{display:none}.imcm{zoom:1} .imcm li{curosr:hand} .imcm ul{zoom:1}.imcm a{zoom:1}</style><![endif]--><!--[if gte IE 7]><style type="text/css">.imcm .imsubc{background-image:url(ie_css_fix)}</style><![endif]--><!--end-->
<!--[imstyles] *** Infinite Menu Styles: Keep this section in the document head for full validation. -->
<style type="text/css">
/* --[[ Main Expand Icons ]]-- */
#imenus0 .imeam span,#imenus0 .imeamj span {background-image:url(bg-daohangS.jpg)width:1pxheight:12pxleft:0pxtop:0pxbackground-repeat:no-repeatbackground-position:top left}
#imenus0 li:hover .imeam span,#imenus0 li a.iactive .imeamj span {background-image:url(bg-daohangS.jpg)background-repeat:no-repeatbackground-position:top left}
/* --[[ Sub Expand Icons ]]-- */
#imenus0 ul .imeas span,#imenus0 ul .imeasj span {background-image:url(stub_arrow_right.gif)width:6pxheight:8pxleft:0pxtop:3pxbackground-repeat:no-repeatbackground-position:top left}
#imenus0 ul li:hover .imeas span,#imenus0 ul li a.iactive .imeasj span {background-image:url(stub_arrow_right.gif)background-repeat:no-repeatbackground-position:top left}
/* --[[ Main Container ]]-- */
#imouter0 {background-color:#95D4CCborder-style:noneborder-color:#CCCCCCborder-width:1pxpadding:0pxmargin:0px}
/* --[[ Sub Container ]]-- */
#imenus0 li ul {background-color:#95d4ccborder-style:solidborder-color:#687a54border-width:1pxpadding:5px 8px 5px 5pxmargin:0px}
/* --[[ Main Items ]]-- */
#imenus0 li a, #imenus0 .imctitle {height:16pxbackground-color:#95D4CCcolor:#000text-align:leftfont-family:Arialfont-size:12pxfont-weight:normaltext-decoration:none padding:3px 6px 1pxmargin:0px 5px 0px 0px}
/* [hover] - These settings must be duplicated for IE compatibility.*/
#imenus0 li:hover>a {background-color:#5B9890text-decoration:none}
#imenus0 li a.ihover, .imde imenus0 a:hover {background-color:#95d4cctext-decoration:none}
/* [active] */
#imenus0 li a.iactive {}
/* --[[ Sub Items ]]-- */
#imenus0 ul a, #imenus0 .imsubc li .imctitle {height:autobackground-color:transparentcolor:#000text-align:leftfont-size:11pxfont-weight:normaltext-decoration:noneborder-style:solidborder-color:#95d4ccborder-width:1px 0pxpadding:2px 5pxmargin:0px}
/* [hover] - These settings must be duplicated for IE comptatibility.*/
#imenus0 ul li:hover>a {background-color:#5B9890text-decoration:noneborder-color:#687a54}
#imenus0 ul li a.ihover {background-color:#5B9890text-decoration:noneborder-color:#687a54}
/* [active] */
#imenus0 ul li a.iactive {}
