Bangpu deposit in Tibet is a large but poorly studied Mo-rich (~0.089%), and Cu-poor (~0.32%) porphyry deposit that formed in a post-collisional tectonic setting. The deposit is located in the Gangdese porphyry copper belt, and formed (~15.32 Ma) at the same time as other deposits within the belt(12~18Ma), although it is located further to the north and has a different ore assemblage (Mo-Pb-Zn-Cu) compared to other porphyry deposits (Cu-Mo) in this belt. Two types of mineralization have been identified in the Bangpu deposit: porphyry Mo-(Cu) and skarn Pb-Zn mineralization. In this paper, based on the whole rock Sr-Nd-Pb and zircon Hf isotopic compositions of the ore-bearing porphyritic monzogranite and Rb-Sr isotopic research on the coprecipitated pyrite and sphalerite, we discuss the mechanism of Mo enrichment at Bangpu and the relationship between the two types of mineralization. Rb-Sr isotope dating of the paragenetic pyrite and sphalerite from the Bangpu Pb-Zn skarn deposit was carried out to figure out the relationship between porphyry and skarn mineralization events.  We got a Rb-Sr isochron age yielded at 13.9±0.9 Ma, which is almost identical to the age of porphyry mineraliztion(~15 Ma). In addition, the account of garnet decreases and the account of both calcite and other carbonate minerals increase, the transformation from high temperature to low temperature skarn mineral compositions, the opaque to translucent sphalerite from the porphyritic monzogranite, suggesting the two types of mineralization in Bangpu deposit are formed in a signal porphyry-hydrothermal system. The (87Sr/86Sr)i values of the monzogranitic porphyry are 0.707504~0.710012 with a small range. The εNd(t) are -3.96~-3.56 while the two stage depleted mantle model ages of Nd isotope are 883~938 Ma. The 206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb values are 18.304~18.439, 15.744~15.793、38.842~38.904, respectively. Zircon 176Hf/177Hf are 0.282826~0.283009 with the mean data of 0.282916, while εHf(t)=2.2~8.7 averaging at 5.4. These data indicate that the ore-bearing monzogranitic porphyry was generated by the mixing process of crust-mantle while mantle component was directly derived from the upwelling asthenosphere and the crust was Lhasa juvenile lower continental crust with amounts of ancient crustal material, this also explains why the Bangpu deposit is enriched in Mo, Pb, Zn for Mo, Pb, Zn are dominately from the ancient crust.