East Kunlun is endowed with abundant gold resources and is nicknamed the “Gold Belt” in China. The Naomuhun gold deposit is just located in the metallogenic belt of Caledonian postarc rifting in the north of East Kunlun. Geochemical studies indicate that quartz diorite which is spatially related to goldbearing rock is of highK calcalkaline series and has the attribute of Andean type epicontinental igneous tectonics. 40Ar39Ar dating yields an average age of 227.84±1.13Ma for sericite. Zircon U-Pb dating yields an age of 235.8±0.8Ma for quartz diorite, suggesting that it formed due to northward subduction of the Animating ocean basin during the middle triassic period. Indosinian is the major gold metallogenic epoch of the East Kunlun area. Therefore, this study is of great importance to further understanding the formation of the Naomuhun gold deposit.