The Shuangjianzishan Pb- Zn- Ag deposit, located in the northeast section of the Huanggang- Ganzhuermiao polymetallic metallogenic belt, is currently the largest silver deposit discovered in China. In this paper, the mineral characteristics of metal minerals in the deposit were studied in detail using field geological survey, identification of the ore facies, back scattering image of the electronic probe and chemical composition of electronic probe. At the same time, the chemical formula of metallic minerals was calculated and the mechanism of silver enrichment was discussed. Silver- bearing minerals occur mainly in the form of visible silver (>50 μm), including independent silver minerals such as polybasite, canfieldite, aguilarite, pyrargyrite, stephanite, freibergite, argentite, kustelite and native silver. Invisible silver content is low and occurs mainly in galena in the form of homomorphism. The metallogenic stage of the deposit can be divided into four stages: (1) Quartz- high iron Se- rich and bismuth galena - rich selenium, tin and antimony silver mineral stage; (2) Quartz- galena- rich iron sphalerite- arsenopyrite- rich antimony and tin, low selenium silver mineral stage; (3) Quartz- sphalerite- galena- silver mineral stage; and (4) Pyrite- carbonate stage. Precipitation order for metallic mienrals is pyrite+chalcopyrite+sphalerite+galena → silver sulfosalt minerals → silver sulfide, and → natural silver. The metal ions such as Fe+, Cu+, Zn+, Pb+ and Ag+ in the deposit are mainly transported in the form of sulfur- hydrogen complexes in the early stage of medium temperature and high sulfur degree. With decreasing of metallogenic hydrothermal temperature, metal S- H complexes such as lead and zinc begin to decompose to form sulphides such as galena, chalcopyrite and sphalerite. During this process, some silver were entraped within these sulphides in the form of microscopic and sub- microscopic enclaves. Precipitation of a large amount of of lead- zinc sulfide significantly changed the composition and properties of metallogenic hydrothermal fluids, eventually resulting in the complete disintegration of silver from its S- H complexes and thus forming a large number of independent silver- bearing mienrals (such as pyrargyrite, polybasite, etc.) through combination with ions such as Cu+ and Sb 3+.With continuous decreasing of temperature and salinity, when sulphur fugacity decreased gradually and pH values increased, free Ag+started to accumulate in the metallogenic fluid and gradually reached saturation, resulting in the precipiation of silver minerals, i.e. argentite due to reaction of Ag+ to H2 S. The mass appearance of natural silver marks the end of the precipitation process of silver.