Abstract: The newly recognized Wulan'gou adakite in the Meilaotewula ophiolite along the Hegenshan suture zone in Inner Mongolia consists mainly of granodiorites. The LA-ICP-MS zircon U-Pb dating shows that the age of the adakite is 279.3±1.4Ma, suggesting a product of Early Permian. The rock has high SiO₂ (65.92%~69.65%), Al₂O₃ (15.30%~17.33%), Sr(359.60×10^-6~734.00×10^-6), and low MgO(1.34%~2.16%), Yb(0.83×10^-6~2.02×10^-6), Y(6.65×10^-6~12.84×10^-6) content, with Na₂O/K₂O ratio varying from 3.95 to 14.09. The adakiteis enriched in large ion lithophile elements K, Rb and Sr, and depleted in high field strength elements Nb, Ta, Ti and P. The total REE is low(32.18×10^-6~65.41×10^-6), whereas REE fractionation is clear((La/Yb)_N=2.84~7.56), without obvious Eu anomaly. All of the geochemical characteristics indicate that the Wulan'gou pluton belongs to high-SiO₂ adakites (HSA). The adakiteis characterized by the island-arc magmatite generated in subduction zone, which suggests that it might have been formed in an island arc setting in petrology and geochemistry. It might have been derived from the intra-oceanic subducted oceanic crust plus sediment partial melting and subsequently melts reaction with overlying mantle wedge peridotite. According to the temporal and spatial distribution and evolution characteristics of the rock assemblage series of pillow tholeiite, boninite, Nb-enriched basalt, High-Mg diorite and adakite in the Meilaotewula ophiolite, the authors suggest that there might have been an intra-oceanic subduction in the Hegenshan suture zone during the Early Permian period.