Aspose.Words.Document dstDoc = new Document(AbsolutePath);
既然是微软的东西,就用Aspose.Words
具体的用法你百度一下Aspose.Words,
string AbsolutePath = ""; // 文件地址
//这个是创建对象
Aspose.Words.Document dstDoc = new Document(AbsolutePath);
//这个是保存
dstDoc.Save(AbsolutePath + ".html", SaveFormat.Html);