The Weilasituo porphyry Sn-W-Rb deposit is newly discovered in Hexigten Banner, Inner Mongolia. It is located at the west of Weilasituo and Bairendaba vein type deposits and genetically related with the quartz porphyry stock that intruded in the Xilinhot Complex and the Carboniferous quartz diorite. The newly discovered porphyry Sn-W-Rb mineralization and its upper vein type Cu-Zn-Pb-Ag mineralization in the Weilasituo and Bairendaba deposits constitute a porphyry-hydrohermal vein type ore system. Four stages of mineralization are recognized based on the mineral assemblages, including: (1) Na-Ca-Sr alteration stage, (2) greisen stage, (3) silica-sericite stage and (4) late barren stage. The Na-Ca-Sr alteration stage is characterized by an alteration mineral assemblage of albite and amazonite, with the Sn-W mineralization occurring as disseminated cassiterite and wolframite in the quartz porphyry, with minor arsenopyrite, Fe-bearing sphalerite and arsenobismite. The greisen stage is characterized by an alteration assemblage of quartz and brown muscovite that overprinted on the Na-Ca-Sr alteration and hosted in fractures as greisen veins, the Sn-W mineralization is mainly occurred as cassiterite and wolframite-bearing greisen vein in fractures, with minor arsenopyrite, pyrite, Fe-bearing sphalerite, chalcopyrite and molybdenite. The silica- sericite stage is characterized by large amount of silica and green sericite, the mineralization in this stage is hosted in fracture as veins and characterized by massive base metal sulfides, including arsenopyrite, pyrite, pyrrhotite, Fe-bearing sphalerite, chalcopyrite, galena, Ag-bearing tetrahedrite. The late barren stage is overprinted on the early stages with illite, kaolinite, chlorite et al. The mineral assemblage indicates the ore-forming fluid is acid, and is of low oxygen and sulfur fugacity. The porphyry- vein type ore system has significant alteration and metal zonation features. The alteration has a Na-Ca-Sr alteration zone in the depth, greisen zone proximal to the quartz porphyry stock, and silica-sericite zone distal to the quartz porphyry stock. The metal zonation feature is characterized by a Sn-W-Rb mineralization core in the porphyry stock, and the copper, zinc, lead and silver mineralization occur outward sequentially from the porphyry stock. Metal fractionation and sequential minerals precipitation from the ore-forming fluid is the main reason for the formation of metal zonation feature. The metal zonation feature is also the indicator of ore fluid movement The ore system is rich in LILE, which indicates magmatic fractionation is the reason for enrichment of metals. The discovery of the porphyry Sn-W-Rb mineralization indicates there is huge exploration potential for Sn-W mineralization in the south Great Xing’an Range.