The NiuxingbaLiumukeng AuAgPbZn polymetallic deposit in the Yinkeng ore field is located in the YuduGanxian ore cluster area, south Jiangxi Province. Field investigation, systematic mineralographical observation, and electronic probe composition analysis indicate that bismuth is one important associated element in the NiuxingbaLiumukeng AuAgPbZn polymetallic deposit, and occurs as an independent mineral or microparticles in internal or marginal parts of early formed sulfide. Bibearing minerals are versatile, including pavonite, matildite, gustavite, berryite, aikinite, emplectite, krupkaite and tetradymite. Compared with Pangushan quartz veintype WBi deposit in the same ore cluster area, two ore deposits contain two Bibearing mineral associations (PbAgBiS and TeBiS), but vary in mineral occurrence and contents. CuPbBi element association is found only in the NiuxingbaLiumukeng deposit. The presence of bismuth minerals suggest the deposit belongs to AuBi（low Te）S system, and formed in the geological environment with medium and low temperature, medium high density and low salinity. Bismuth migrated in the form of sulfide complexes after massive gases escaping and sulfur fugacity increasing which was compelled by boiling oreforming fluid derived from magma. With precipitation of sulfide (e.g. pyrite), a large amount of sulphur were transferred into goldbearing minerals and telluride. Further decreasing of temperature and sulfur fugacity during the evolution of oreforming fluid resulted in deposition of bismuth sulfosalt minerals at the late stage of mineralization. Bi promoted gold migration and enrichment during the process of mineralization. Bibearing minerals at the two deposits present some differences in occurrence state, chemical components, forming environment, and precipitation mechanism, suggesting Bi’s preference in oreforming process and thus playing a significant role in tracing oreforming material source.