In Baiyin Copper mine one million tons of original design annual capacity has not yet been achieved ever since it was put into production. All factors which cause the failure were analyzed, leading to the conclusion that one million tons capacity is limited technically and unreasonable economically. In the meantime, production capacity of level ore block and capacity balance diagrams indicated that a capacity of 0.75 million tons is rational and this conclution was verified through economically rational service life, rational downward mining rate and development of new level. It was proposed that in the mine some technical modifications cvere needed in order to ensure a stable annual production capacity of 0.75 million tons ore in the service life.