这应该工作...
http://jsfiddle.net/it_levon/ew4MP/
<div class='cssmenu'>
<ul>
<li class='active '><a href='index.html'><span>Home</span></a></li>
<li><a href='#'><span>Products</span></a>
<ul>
<li><a href='#'><span>Product 1</span></a>
<ul>
<li><a href='#'><span>blue</span></a></li>
<li><a href='#'><span>red</span></a></li>
</ul>
</li>
<li><a href='#'><span>Product 2</span></a>
<ul>
<li><a href='#'><span>green</span></a></li>
</ul>
</li>
</ul>
</li>
<li><a href='#'><span>About</span></a></li>
<li><a href='#'><span>Contact</span></a></li>
</ul>
</div>
CSS...
.cssmenu{
border:none;
border:0px;
margin:0px;
padding:0px;
font: 67.5% 'Lucida Sans Unicode', 'Bitstream Vera Sans', 'Trebuchet Unicode MS', 'Lucida Grande', Verdana, Helvetica, sans-serif;
font-size:14px;
font-weight:bold;
}
.cssmenu ul{
background:#333333;
height:35px;
list-style:none;
margin:0;
padding:0;
}
.cssmenu li{
float:left;
padding:0px;
}
.cssmenu li a{
background:#333333 url('images/seperator.gif') bottom right no-repeat;
color:#cccccc;
display:block;
font-weight:normal;
line-height:35px;
margin:0px;
padding:0px 25px;
text-align:center;
text-decoration:none;
}
.cssmenu li a:hover, .cssmenu ul li:hover a{
background: #2580a2 url('images/hover.gif') bottom center no-repeat;
color:#FFFFFF;
text-decoration:none;
}
.cssmenu li ul{
background:#333333;
display:none;
height:auto;
padding:0px;
margin:0px;
border:0px;
position:absolute;
width:225px;
z-index:230;
/*top:1em;*/
}
.cssmenu li ul li ul {
margin-left:225px;
margin-top:-35px;
}
.cssmenu li:hover > ul{
display:block;
}
.cssmenu li li {
background:url('images/sub_sep.gif') bottom left no-repeat;
display:block;
float:none;
margin:0px;
padding:0px;
width:225px;
}
.cssmenu li:hover li a{
background:none;
}
.cssmenu li ul a{
display:block;
height:35px;
font-size:12px;
font-style:normal;
margin:0px;
padding:0px 10px 0px 15px;
text-align:left;
}
.cssmenu li ul li:hover {
background:#2580a2 url('images/hover_sub.gif') center left no-repeat;
border:0px;
color:#ffffff;
text-decoration:none;
}
.cssmenu p {
clear:left;
}