本文透過道教重玄思想集大成者唐初道士成玄英《道德經開題序許義疏》，考察做為一代道門宗師的成氏，如何站在道教的角度，融通佛教中觀思想。 本文皆析成玄英道佛融通的思想，除見其同，更顯其異。目的重在凸顯成玄英的道士立場及其所承之道教教義學傳統。 因此本文採取概念詮釋與思想史的研究方法，進行思想系統之「形式」與「內容」的分析。除了比較成玄英「重玄」之道與佛教中觀思想，在具有「形式」性質的「哲學方法」上之異同外，也將對勘具有「內容」性質的兩教「教義」。進而展現成玄英承繼道教教義學傳統，融通佛教中觀思想的哲學方法，以建構其「重玄」之道的道教義學體系。

This article through Cheng Hsuan-Ying who was the master of Twofold Mystery thought, consider how he standed in the angle of religious Taoism, to resolve the view point from Buddhism. We will analysis Cheng Hsuan-Ying’s thought in addition to seeing it s similar element, even showing its difference between Taoism and Buddhism. The purpose is to emphasize the Taoist priest position of Cheng Husna-Ying and the doctrinal tradition of religious Taoism that he accepted.