The large-scale tectono-magmatism and mineralization during Mesozoic in eastern North China Craton resulted from the subduction of paleo-Pacific plate, although the starting time of subduction is still in dispute. In this study, the granitoids from Yaowangmiao-Mopan Mountain pluton in Xingcheng area, western Liaoning Province, were taken for systematic researches, including petrology, zircon U-Pb dating, geochemistry and zircon Hf isotopic analysis. Magmatic zircons yielded weighted mean ages of 193 Ma and 186 Ma, so the Yaowangmiao-Mopan Mountain pluton was emplaced during Early Jurassic. The granitic rocks are composed of quartz monzonite, granodiorite, monzogranite and syenogranite. All of these rocks have high total alkalis content and quasi-aluminous to weakly peraluminous characteristics, belonging to the high-K calc-alkaline series with geochemical characteristics similar to those of I-type granite. These rocks are enriched in LREE and K, Pb and depleted in Nb, Ta, Ti and P. The magmatic zircons of the Early Jurassic granitoids have negative εHf(t) (-12.94~-7.39) and ancient t_DM2 values (2.05~1.69 Ga) which indicates that the primary magma was derived from the partial melting of ancient continental crust probably with the mixture of mantle source materials. The Early Jurassic granitic rocks in Xingcheng area of western Liaoning Province have rock assemblages and geochemical characteristics similar to the granitoids formed under the active continental margin related to the subduction of paleo-Pacific plate. The results in this study and regional geological data all indicate that the subduction of paleo-Pacific plate began during Late Triassic-Early Jurassic, and the Early Jurassic granitic magmatism resulted from the response to the subduction of paleo-Pacific plate in eastern North China Craton.