td, input {
vertical-align: middle;
}
如果这不起作用，您将需要发布更多代码才能获得一个好的答案。
假设没有使用其他CSS，则默认情况下应垂直对齐中间。 ...您的问题可能与文本和输入不一样的线高度有关。
td{
line-height:40px;
height:40px;
}
到目前为止，请感谢所有人的帮助。线高和高度添加纠正了这两个文本的垂直对准，但也显着增加了行间间距。如果我将保证金，填充和边界设置为0，这不会改善。我无法将高度降低到小于40px，或者对准会再次失败。
<!DOCTYPE HTML>
<html>
<head>
<meta charset=utf-8>
<title>Table test</title>
<style type="text/css">
.s0 {
font-family: Arial, Helvetica, sans-serif;
font-size: 13px;
}
.s1 {
font-family: Arial, Helvetica, sans-serif;
font-size: 13px;
vertical-align: middle;
line-height: 40px;
height: 40px;
}
.s2 {
font-family: Arial, Helvetica, sans-serif;
font-size: 13px;
vertical-align: middle;
line-height: 40px;
height: 40px;
padding: 0;
margin: 0;
border-width: 0;
}
</style>
</head>
<body>
<pre> font-family: Arial, Helvetica, sans-serif;
font-size: 13px;</pre>
Col1 captions have different vertical alignment to Col2 but inter-row spacing is good.
<table>
<tr>
<td class="s0">Col1</td>
<td class="s0">Col2<input type="text"></td>
</tr>
<tr>
<td class="s0">Col1</td>
<td class="s0">Col2<input type="checkbox" checked><input type="text" value="ABC"></td>
</tr>
<tr>
<td class="s0">Col1</td>
<td class="s0">Col2<input type="text"></td>
</tr>
</table>
<pre> font-family: Arial, Helvetica, sans-serif;
font-size: 13px;
vertical-align: middle;
line-height: 40px;
height: 40px;
</pre>
The two column captions are now at the same height but the inter-row spacing has increased
<table>
<tr>
<td class="s1">Col1</td>
<td class="s1">Col2<input type="text"></td>
</tr>
<tr>
<td class="s1">Col1</td>
<td class="s1">Col2<input type="checkbox" checked><input type="text" value="ABC"></td>
</tr>
<tr>
<td class="s1">Col1</td>
<td class="s1">Col2<input type="text"></td>
</tr>
</table>
<pre> font-family: Arial, Helvetica, sans-serif;
font-size: 13px;
vertical-align: middle;
line-height: 40px;
height: 40px;
padding: 0;
margin: 0;
border-width: 0;
</pre>
Padding, margins and border reduced to 0 but still greater inter-row spacing
<table>
<tr>
<td class="s2">Col1</td>
<td class="s2">Col2<input type="text"></td>
</tr>
<tr>
<td class="s2">Col1</td>
<td class="s2">Col2<input type="checkbox" checked><input type="text" value="ABC"></td>
</tr>
<tr>
<td class="s2">Col1</td>
<td class="s2">Col2<input type="text"></td>
</tr>
</table>
</body>
</html>