Granitoids are widely distributed in Baluntai area, Central Tianshan Mountain. The LA-ICP-MS age of granitoids which are located in north of the Wuwamen fault are 452.7±1.4Ma and 455.5±1.7Ma. Geochemitry results show that major elements belong to metaluminous calcalkaline rocks series, and REEs are characterized by righttype distribution patterns and higher LaN/YbN（6.01~23.74）with weak negative Eu anomaly (δEu=0.67~0.83). In addition, they display LILE enrichment of Ba, Rb and Cs. HFSE depletion of obviously Nb and Ta negative anomalies, and slight Ti depletion. The results of Hf isotopes show that εHf(t) values vary from -14.8 to -9.4, with an average of -12.4, and TDM2values vary from 1730 to 1997Ma, with an average of 1871Ma. The geochemical characteristics show that late Ordovician granitoids, which was the product of Early Proterozoic lower crust partial melting because of mantlederived magma underplating brings a lot of heat, have characteristics of volcanic arc granites. Therefore, the Late Ordovician granitoids are considered as the earliest magma record of South Tianshan ocean basin northward subduction in the Baluntai area, Central Tianshan Mountains.