Eastern Guangdong Province is located at the southeast end of the NE vo lcanic belt of the coast of southeastern China. The Mesozoic v olcanic—intrusive complexes crop out widely over the district. Based on st udies of PbNdSr multielement isotopic systems,it is held in this paper that the r ockforming machenism on the granitic volcanic—intrusive complexes is anatexite (equilibrium partial melting) of the continental crust.The source r ocks of the complexes are old basement rocks cropping out in the neighbouring ea st ern Fujian and Zhejiang, but in this region. The composition of the source rocks is not homogeneous, and is the mixed materials or interclay of crustal sedimen t s and mantle volcanic rocks in the crust.