Ore-bearing porphyry in Mengxi porphyry Copper-Molybdenum deposit is plagiogranite porphyry.The geochemical and Sr-Nd-Pb isotope research of porphyry bodies show that rocks are peraluminous calc-alkaline,enriched in large-ion lithophile elements Rb,Ba,U,K,Pb,Sr and depleted in high field strength elements Th,Ta,Nb,Nd,Ti.Through the studies on porphyry bodies,it is identified for rock bodies characterized with low(87Sr/86Sr)ⅰratio(0.7046 5~0.7053 7) and high εNd(t) value(- 2.2~6.6).(206Pb/204Pb)i ratio of th...