Mazhengji 馬政記, full title Da-Yuan mazheng ji 大元馬政記 "Horse administration of the Great Yuan", is a book on the regulation of the horse trade during the Yuan period 元 (1279-1368) written under the supervision of Wen Tingshi 文廷式 (1856-1904), courtesy name Yunge 芸閣, style Daoxi 道希, during the late Qing period 清 (1644-1911).
The main text is based on unpublished records by Xu Xingbo 徐星伯. The Mazhengji is 2-juan long and is divided into several chapters covering the topics government purchase (hemai 和買), selection of horses (shuama 刷馬), taxation (choufen 抽分), and various rules for horse administration (mazheng zali 馬政雜例).
The regulations are quite detailed and explain how during the pre- and early Yuan period horses were purchased, bred and dealt with. One regulation, for instance, says that it was forbidden for subjects of the khan to cross the Yellow River by horse, in order to forestall the export of beasts to the Song empire 宋 (960-1279).
Ke Shaomin 柯紹忞 (1850–1933), author of the history Xinyuanshi 新元史, stresses the importance of this book that is a valuable supplement to the very short chapter on horse administration in the official regulations of the Yuan empire.
The book is included in the series Guangcangxuequn congshu 廣倉學宭叢書 and was reprinted in 1937 by the Beiping Wendiange Shuzhuang Company 北平文殿閣書莊.