Zixue san is a preparation in Chinese Pharmacopoeia ，and is a commonly used representative formula in Liangkai formulation. In the previous editions of Chinese Pharmacopoeia ，for the item of the formulation and preparation method of Zixue san，“mirabilite”“mirabilite（prepare）”“Xuanming powder ”and other different descriptions have been repeatedly modified and amended；the methods of preparation of mirabilite in the processing specifications of different provinces and cities are also different，causing effects in actual production. Therefore ，the author has researched the historical evolution of Zixue ，the formulation and preparation method of Zixue san in the previous editions of Chinese P harmacopoeia，and has expounded the change process of mirabilite，mirabilite（prepare），Xuanming powder in the item of formulation and preparation method of Zixue san. In addition ，the author compares Chinese Pharmacopoeia with the processing methods of mirabilite in the national and provincial processing specifications ，in order to provide a basis for the processing of mirabilite in the formulation of Zixue san.