文本节点上没有命名空间；您的 three 节点只包含文本 foo:Delta，它在 XML 中没有特殊含义.您可以使用 starts-with:

There is no such thing as a namespace on a text node; your three node just contains the text foo:Delta, which has no special meaning in XML. You can find nodes holding text starting with foo: using starts-with:

//*[starts-with(., "foo:")]