Edit in JSFiddle

<h1>大标题</h1>
<p>文字</p>
<h1>大标题</h1>
<p>文字</p>
<h1>大标题</h1>
<p>文字</p>
<h1>大标题</h1>
<p>文字</p>

h1:before{
    content:'第'counter(my)'章';
    color:red;
    font-size:42px;
}
h1{
    counter-increment:my;
}