Abstract: The large-scale Huaaobaote vein type of Ag-Pb-Zn polymetal deposit in Xi Ujimqin Qi, Inner Mongolia, occurring in the fracture zone in Lower Permian Shoushan formation, is of subvolcanic meso-epithermal genesis. The deposit is located in the Xilinhot-Huolin Gol polymetal metallogenetic belt in the middle-south of Daxinganling Mountains, with developed faults and intense volcanic activities. The metallogenesis of Ag-Pb-Zn polymetal is in multiple stages. The vein-shaped ore bodies are in medium scale, complex shapes, stable thickness, evenly distributed components, and controlled by NW-, NE- and N-S-trending faults. The wall-rock alterations are developed in 3 stages, with obvious zonation. The metallogenic epoch is Late Jurassic.