Abstract: To investigate the leaching characteristic of alkaline copper dioxide ore by ammonia producing bacteria, the influence of the ammonia producing bacteria on the ore during the process was analyzed. To expose the possible influence factor, the shaking flask leaching test was carried out by putting alkaline cupric oxide ore from Yunnan separately into five kinds of leaching solutions, such as bacteria-containing, bacteria-removing inoculums and ammonia solution. Experimental results indicate that the bacteria have a strong ability at producing ammonia and the highest ammonia mass concentration reaches 8. 93 g·L^-1. Ammonia production is positively correlated with the content of bacteria. The bacteria leach mineral mainly through producing ammonia, besides, the bacteria and their metabolites can also effect. The leaching capacity is in the order of bacteria ammonia > bacteria > bacterial metabolites, and the ratio of the three is 12:5:4.