The Method of Summoning of Emissary Zhang張使者法inherited from Mo Yueding莫月鼎was one of the most important rituals and Methods of Divine Empyrean (Shenxiaofa神霄法) in Yuan-Ming Dynasty, which insofar we know nearly nothing about. In fact, there are numerous manuscripts and related texts collected in Daofa Huiyuan道法會元and Fahai Yizhu法海遺珠, along with those found in libraries and private collections, from which we can figure out how the Magic of Summoning Emissary Zhang functioned and which part of the content has been changed. With careful analysis and examination based on these texts, we can have some clue for certain kinds of general practice of the Magic of Summoning Emissary Zhang. Such research will help provide understandings of the inner structure and development of this newly-built ritual tradition.