Beiya gold mine is representative in Jinshajiang—Ailaoshan alkali- rich porphyry metallogenic belt. Many scientific studies have been carried out on the genesis, diagenetic ore- forming relations, ore- forming fluid properties and material sources. However, there is a lack of systematic mineralogical research. In this paper, we have studied mineral association and occurrence of gold minerals during gold mineralization. The results show that gold minerals are main of natural gold, followed by kustelite and electrum. The assemblage in gold mineralization is gold minerals + silver minerals + pyrite + chalcopyrite + galena + sphalerite + arsenopyrite + magnetite + siderite + covellite. Gold minerals are mainly fissured gold and encased gold, followed by inter- granular gold, and mainly occurring in pyrite, galena, chalcopyrite and other sulfides, as well as quartz, biotite and other gangue minerals, indicating that the ore- forming fluid is dominated by gold, iron, copper, lead, sulfur, silicon and other elements.