Abstract: Analyses of regional geologic settings and geophysic data have yielded following results: 1. The regional tectonism and material composition of basement had influence on the Late Mesozoic magma activity，and the magmatic division at the surface is consistent with that in the deep. 2. Based on the types of magmatic rocks，three tectonic-magma regions are recognized: (a)low-K and high-A1 calc-alkaline intermediate-acid volcanic-intrusive complex region, i.e., SE China Coastal Region; (b)high-K granitic volcanic-intrusive complex region，named as the Wuyishan region and (c)high-K S-type granite region in the west to Ganjiang without acid volcanic intrusive complex These three regions are separated by Zhenghe-Dapu and Ganjiang fault zones respectively. The crusta1 thickness in the SE China Coastal Region is thinner, whose basement is mostly volcanic and granite belongs to I-type; the crustal thicknesses for other two regions are greater than the first，their basements are mostly melted sedimentary rock series and the granitic rock is S-type. The Ganjiang fault zone is called as the Late Mesozoic Volcanic Rock Line 3. In the SE China Coastal Region，there is a local-low-resistivity-layer，which was related to a pullrifting The underplating of basaltic magma an d the formation of alkaline granit were closely related to the pull-rifting in the Late Cretaceous. 4 .Zhenghe-Dapu，Ganjiang and Changle-Nan ’ao fault zone have apparent geophysic features，which are both the gravity gradient zones and ultra-crust fault zones where the geological interaction along the crust. mantle boundary is most common. 5. There is a low-velocity zone of 2-4km thick in the middle crust, and is considered as a result of a part melting of ductile deformation，which is probably a local magrnatic source 6. Our study supports the model of plate subduction combining with underplating of basalt magma For the origin of the Late Mesozoic magmatism in the SE China . The fault zone from the Japanese Central Tectonic Line to Taiwan Longitudinal zone is a Mesozoic subduction and suturing zone where the Mesozoic Pacific plate subducted to the East Asian continental margins to form a wide volcanie-intrusive arc.