The Sandaomingshui deposit, located at the western part of the Beishan district, is a recently discovered medium-sized Cu-Zn deposit. Aim to understand its genesis type and controlling factors, geological characteristic of the Sandaomingshui Cu-Zn deposit is studied in this paper. According to the alteration features, mineral assemblages and crosscutting relationships, the mineralization and alteration process have be divided into the early-(stage Ⅰ), middle-(stage Ⅱ) and late-mineralization (stage Ⅲ) stages. The early-mineralization stage is characterized by the occurring of pyrite±chalcopyrite±sphalerite and pyrite-sphalerite±chalcopyrite veins, and disseminated pyrite-chalcopyrite-sphalerite assemblage, with chlorite±sericite alteration occurred in wall rocks, which are similar to VMS-type deposits. The middle-mineralization stage, main mineralization stage, is marked by phyllic alteration and chalcopyrite-pyrite-sphalerite assemblage, in which Cu-Zn-rich minerals (chalcopyrite and sphalerite) occurred during ductile deformation. The late-mineralization stage is featured by the quartz±chalcopyrite±molybdenite±pyrite and calcite veins, with unconspicuous alteration, which were hosted by open fractures. According to the alteration and mineralization features of the Sandaomingshui Cu-Zn deposit and regional mineralization characteristics, Cu-Zn mineralization of the Stage Ⅰ was likely VMS-type. The stage Ⅱ Cu-Zn mineralization overprinted on the stage I and formed the major Cu-Zn orebodies of the Sandaomingshui, which was controlled by ductile shear zones. The stage Ⅲ Cu-Mo mineralization superposed on the earlier Cu-Zn mineralization.