Abstract: The eprformance and design parameter of grinding mill used in mineral processing plant of Yongping Copper Mine is introduced in this paper.As grinding operation couldn, t meet the needs of flotation technology and the ball consumption was very great under the primary design conditions.so partial adjusting design parameter, experiments of ball consumption in grinding mill were carried out, in order to choose steel ball which could fit ore properties of Yongping Copper Mine.After choosing suitable steel ball as grinding medium of grinding mill, steel ball per unit consumption decreased to 1.2kg/t while it was 2.06kg/t during the initial post -production period, which is benefit for reducing production cost.