Objectives: Adakite is a kind of intermediate—acid rock with unique geochemical characteristics. It can track the oceanic crust subduction and crustal thickening and other related events in geological history, which is of great significance for the inversion of crustal composition and mineralization. According to previous studies, the granites of Seerbeng and Nuhetingshala in West Ujimqin have the characteristics of adakite, but lacked accurate chronology data. The study on the diagenetic age and tectonic background of the adakite granitoids is helpful to understand the tectonic evolution of the paleo- Asian Ocean. Methods: Based on the field work，through the microscope observation，the whole rock chemical analysis, LA- ICP- MS U- Pb zircon dating of the granitiods and the Hf isotopic analysis. Results：The U- Pb isotopic dating of zircon shows that the ages of Seerbeng pluton and Nuhetingshala pluton in West Ujimqin area are 255.3±0.71Ma and 254.4±1.2Ma, which are the products of magmatic activity in the late Permian.By lithology and rock geochemistry analysis found that belong to calcalkalic rock and high potassium calcalkali series, SiO2 content is 65%~73%, Narich and K- poor, high Sr, low Yb Y and high Sr/Y, wich consistent with the characteristics of typical adakite.The magmatic zircons are positively εHf(t) values (+8.1~+13.3) and young two- stage model ages varied in 430~760Ma. Adakite rock formation is related to partial melting of young subduction plate,and the high Mg# indicates that magmatic melts interact with mantle peridotite. Conclusions: Combined with regional rock assemblages, the paleoAsian Ocean has not yet completely closed in late Permian. During this stage, the subducted oceanic crust broke off and partially melted, which formed the adakite granitoids and hightMg andesite. The closing time of the paleoAsian ocean should be after the Permian.