Mesozoic intrusions in Tongling area consist of gabbro，quartz diorite and granodiorite with an age of 137 Ma士·These intrusions are characterized by relatively high K2O，whole alkali and Sr contents but comparatively low Cr and Ni contents，belonging to K-high calc-alkaline series. They contain homoeogene enclaves such as pyroxenolite.hornblendite and hornblende-pyroxnolite.which are cumulates. The basic member of the intrusive rocks is silica undersaturated .which formed silica一oversaturated rocks by assimilation. Petrological and isotopic data show that the intrusive rocks from’ I'ongling area might have been formed by AFC mixing process，with the basic end-member being alkali basaltic magma and the acidic end-member being old granulite facies rocks in lower crust. AFC modeling calculation shows that AFC mixing curve with r=0. 75 ,DNd=0.5 and Dsr=0.5can can well fit the modal data of the intrusive rocks from Tongling area.