您可以将段落设置为弹性框，并使用space-between模拟对齐。

p {
  display: flex;
  justify-content: space-between;
}

<p><span>Hello</span><span>I</span><span>am</span></p>

如果你想让它看起来像你在一个普通段落上得到的普通的对齐方式，那么你可以使用text-align：justify-在每个span上使用after伪元素放置空格：

p {
  text-align: justify;
}

span::after {
  content: ' ';
}

<p><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span><span>Hello</span><span>I</span><span>am</span>  </p>