Abstract: Pb-Sr-Nd isotopic ratios and element compositions of the gabbros from Jinan and Zouping have been studied. We obtain that (87Sr/86Sr)i＝0.7041~0.7056，εNd(t )＝-6.0~-13.0，( 206Pb/204Pb)i = 16.545~16.998，(207Pb/204Pb)i = 15.242~15.350，(208Pb/204Pb)i = 36.488~36.944 (except for SD792 possessing highly radiogenic Pb isotopic characteristics) . Trace element characters are not indicative of the source of the gabbros because of their cumulate nature. A comparison with typical EMⅠtype oceanic and continental basalts suggests that the mantle source of the Jinan and Zouping gabbros shows an isotopic characteristics similar to that of the EMⅠmantle，but with a significant contribution of the lower crust based on Pb isotopic diagrams. The addition of the lower crust into the mantle may be related to the subduction of the Pacific Ocean Plate, which resulted in the lower crust delamination.