The Purang Pluton is located in the south margin of Qiangtang, Xizang(Tibet), consisting of Quartz monzonite, monzonite and monzodiorite．It intruded the limestone of the Triassic Riganpeiqun Group, accompanying with skarn type magnetite mineralization．The study of the pluton is scare．Our research mainly focuses on the formation age and the petrogenesis of quartz monzonite in the Purang area．In addition, here we also discuss its metallogenic significance．