(https://img-ask.csdn.net/upload/201711/24/1511514878_233753.jpg)
<th style="white-space:nowrap" >内容 不会 再换行 折行 了</th>
试了一下不会啊
<html>
<head>
<style type="text/css">
table.one
{
table-layout: automatic
}
table.two
{
table-layout: fixed
}
</style>
</head>
<body>
<table class="one" border="1" width="100%">
<tr>
<th width="20%">10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000</th>
<th width="40%">10000000</th>
<th width="40%">100</th>
</tr>
<tr>
<td width="20%">100</td>
<td width="40%">10000000</td>
<td width="40%">100</td>
</tr>
</table>
<br />
<table class="two" border="1" width="100%">
<tr>
<td width="20%">100000000000</td>
<td width="40%">10000</td>
<td width="40%">100</td>
</tr>
</table>
</body>
</html>
建议col-xs-12，这个是支持全部格式的