Bangpu in Tibet is a large but poorly studied Mo-rich (~0.089%), and Cu-poor (~0.32%) porphyry deposit formed in a post-collisional tectonic setting. The deposit is located in the Gangdise porphyry copper belt (GPCB), and formed at the same time (~15.32 Ma) as other deposits within the belt (12~18 Ma), although it is located further to the north and has a different ore assemblage (Mo-Pb-Zn-Cu) compared with other porphyry deposits (Cu-Mo) in this belt. Two distinct mineralization events have been identified in the Bangpuhyry deposit, which are porp Mo-(Cu) and skarn Pb-Zn mineralization. According to detailed drilling catalog and study of mineral assemblages and vein intersection relationship in 11 drill holes, veins in the Bangpu deposit can be divided into three types, which are A, B, D veins respectively. Also, minerals such as garnet and epidote are also been detected which can help to invert fluid evolution process in the skarn mineralization period. Along the circular alteration zonation from a central potassic alteration zone through silicification and phyllic alteration zones to an outermost propylitic alteration zone, argillic alteration is present as patches within the phyllic and propylitic alteration zones. Skarn alteration is identified by the presence of typical skarn minerals within the surrounding rocks. A-type veins contain fluid inclusions that generally homogenize between 320℃ and 550℃, and have w(NaCl_eq) values that are generally split between salinities of 17.0%~22.0% (gas-liquid two-phase inclusions) and 30.8%~67.2% (crystal-bearing inclusions); fluid inclusions within B-type veins generally homogenize at temperatures between 380℃ and 550℃, and have w(NaCl_eq) values that are clustered within three distinct intervals, i.e., 1.6%~10.1%, 23.2%~24.5% (gas-liquid two-phase inclusions), and 30.8%~67.2% (crystal-bearing inclusions); fluid inclusions within D-type veins have homogenization temperatures and salinities of 213~450℃ and 7.3%~11.6%, respectively. Fluid inclusion microthermometry indicates that the ore-forming fluids related to the porphyry mineralization evolved from high-temperature and high-salinity fluids to low-temperature and low-salinity fluids. Intense boiling occurring in A, B veins indicates that pressure fluctuation contributed a lot to the deposition of Mo and Cu. 16 quartz samples related to porphyry mineralization have the following H-O isotope data: δD_V-SMOW=-185.8‰~-107.1‰,δ¹⁸O_V-SMOW=9.5‰~14.5‰, while δD_V-SMOW=-184.7‰ ~-126‰,δ¹⁸O_V-SMOW=3.9‰~12.9‰ for garnet, epidote, quartz, and calcite related to skarn mineralization. δ¹⁸O_V-SMOW = -1.6‰ ~10.4‰, δC_V-PDB=-6.5‰ ~-3.4‰ for calcite in porphyry period and δ¹⁸O_V-SMOW=1.8‰~11.9‰, δC_V-PDB=-5.1‰~4.6‰ for calcite in skarn period. All the C-H-O isotope data demonstrate two processes of fluid evolution in the Bangpu porphyry-skarn deposit, i.e., dehydration-degassing process and atmospheric precipitation addition process.