Petrochemistry and isotope geology of the Late Mesozoic volcanic-plutonic rocks from the Da Hinggan Mts. and the Yanshan Mts. in north China are studied. The results indicate that the formation and evolution of magmas in this area are related to intraplate magmatic activities under an extensional environment but not directly related to the subduction of Pacific Plate. In this ppaper, high resolution tomographic images across Japanese Trench-Changbai Mts. -Erden Cagaan of Mongolia are displayed, delineating the shape of the subducted Pacific slab, which in combination with the subduction time and time-lag between the subduction and magmatism, further proves the independence of the magmatic activities from the plate subduction. Finally, chronological research of underplating connects the Mesozoic magmatic activities in the Da Hinggan Mts. -Yanshan Mts. with the upwelling of the sub-continental asthenosphere displayed by the tomograghic images.