 "Qianxisaurus" was first described and named by Yen-Nien Cheng, Xiao-Chun Wu, Tamaki Sato and Hsi-Yin Shan in 2012 and the type species is "Qianxisaurus chajiangensis".The generic name is derived from "Qianxi", which refers to the western part of Guizhou Province where the holotype was found, a spelling based on the Chinese Pinyin, and from Greek "saurus", meaning "lizard", a common suffix for genus names of extinct reptiles.The specific name is derived from "Chajiang", a town near which the specimen was collected, with the edition of the Greek suffix "-ensis", meaning "from".