试试这个：

    XmlDocument xmlDoc = new XmlDocument();
    xmlDoc.Load("../../XMLFile1.xml");
    XmlNode node = xmlDoc.SelectSingleNode("/SETTING_LIST/setting[name='first']");
    foreach (XmlNode nd in node)
    {
        richTextBox1.Text += nd.OuterXml + "\n";
    }

另请参阅以下类似文件：

Also please refer to the following similar documents:

如何：查找同级节点（XPath-LINQ to XML）（C＃）

从中获取兄弟姐妹给定节点

问候，

Stanly