The Mamupu copper- polymetallic deposit in Tibet is an important part of the southern section of the Yulong copper belt. The latest exploration progress reveals that the amount of copper and gold resources in the Mamupu copper- polymetallic deposit has reached a medium scale, but the theoretical research is still very weak. Based on systematic microscopic identification and electron probe analysis, this paper studied the mineralogy of Mamupu copper polymetallic deposit in detail, and then explored the genesis of the deposit. The main ore body in the Mamupu deposit is a medium- thick plate breccia- type orebody. The ore type is mainly breccia, and partial lenticular ore bodies were produced in hornstones. Extensive chlorite,keratinization, phlogopite and weak sericite alteration are developed in the mining area. The results of electron probe analysis show that the pyroxene is mainly diopside, the mica is mainly phlogopite, and the amphibole is mainly tremolite in skarn minerals. The metallogenic stage and mineral assemblage of the Mamupu deposit are as follows: Ⅰ prograde metamorphic stage, the mineral assemblage is diopside- garnet- magnetite±scheelite; Ⅱ retrograde metamorphic stage, the mineral assemblage is tremolite- phlogopite- magnetite±chlorite±epidote±scheelite; Ⅲ sulfide stage, mineral assemblage is pyrite- chalcopyrite±molybdenite±pyrrhotite±bismuthinite±galena±sphalerite±fluorite±quartz, mainly metallogenic stage; Ⅳ carbonate stage, mineral assemblage is hematite±fluorite±calcite±quartz±chalcedony. The mineralogical characteristics show that the evolution of skarn experienced a process from high temperature to medium and low temperature after the magmatic period. With the decrease of temperature, magnesian skarn minerals changed from diopside in prograde metamorphic stage to phlogopite in retrograde metamorphic stage. Skarn formation experienced a relatively oxidized environment in the early stage to a relatively reductive environment in the late stage.The breccia in the mining area are dolomitic and calcareous carbonate interlayers in the original sedimentary strata, and most of the carbonates are breccia due to extensive hydrothermal metasomatism. The ore- bearing magmatic hydrothermal fluids emplaced and metasomatism occurred along the occurrence of carbonate rocks, resulting in the precipitation and enrichment of metal minerals in breccia strata.