Southeast coast of China lies in the plate junction between the Pacific and the Eurasian plates, where volcanic rocks are widely exposed and large-scale mineralization were developed in the Mesozoic. The studies of major elements, trace elements and REE suggest that the source of mafic volcanic rocks is separated from the source of acidic volcanic rocks. The remelting of the lower crust caused by heat from basaltic underplating which was widespread in southeast coast of China in the Mesozoic generated a lot of acidic volcanic rocks. The intermediate volcanic rocks, geochemical characteristics of which are controlled by acid volcanic rocks, are generated by mixing of acid magma and mafic magma.