Late Paleozoic post-collisional granitoid intrusions are extensively developed in West Junggar and even in the whole northern Xinjiang. The Kulumusu series of Kulumusu batholith in the Wuerkashier of West Junggar, which is one of these intrusions, mainly comprises monzogranite, fine-grained syenogranite, middle-coarse-grained syenogranite, alkali feldspar granite and K-feldspar porphyry. The Kulumusu series is characterized by high silica (SiO₂=70.78%～76.85%), alkali (K₂O+Na₂O=7.87%～9.71%), and low titanium and calcium (TiO₂=0.08%～0.41%, CaO=0.16%～1.42%), thus belonging to metaluminous to strongly peraluminous series (ACNK=0.98～1.15). The rocks display "V"-shaped REE patterns, and are evidently depleted in Eu. They are enriched in light rare earth elements (Rb, Th, K) and high strength field elements (Zr, Hf), and significantly depleted in Ba, Sr, P and Ti. These features indicate that the Kulumusu series belongs to A₂-type granite. In combination with the tectonic evolution of this region, the authors hold that the Kulumusu series was formed in a post-collisional tectonic setting.