Abstract: Devonian is one of the most widely outcropping strata in Xinjiang. Lower Devonian at Beita Mountain in Qitai country is formed by Zhuomubasitao formation, which is rich in fossils like brachiopod, coral, trilobites, bryozoans, endoceratida, ammonites, and the brachiopod accounted for more than 90% of them. The brachiopod fauna includes 24 genera and 48 species. According to the composition of this brachiopod fauna, it could be named as the Eastern Junggar Spinatrypa khalfini Fauna, which is characterized by atypa and spirifer. The fauna can be divided into two brachiopod assemblages, such as the Leptocoelia sinica assemblage in the lower part and the Spinatrypa khalfini assemblage in the upper part. Based on the comparison of brachiopod faunas among lower Devonian Aobaotinghundi formation in Inner Mongolia, Jinshui formation, Huolongmen formation, Heitai formation and Wunuer formation in Northeast China, the age of Zhuomubasitao formation is confirmed to be the Emsian.