The ball mill is indispensable equipment in ore-dressing process,and the bearing is a key part to support the rolling cylinder of the mill,reduce friction coefficient and ensure rolling precision.In light of the problems like big transmission resistance,high power consumption and malfunction rate happening when sliding bearing is used in traditional long-cylinder ball mills,renovation on the bearing of ball mills are carried out.The paper describes the technical renovation ideas and process.The self-aligning roller bearing that has big load capacity and can endure big impact load are equipped to replace traditional sliding bearing.Industrial application shows that the self-aligning roller bearing can improve equipment function rate,prolong equipment life and is cost-effective.The renovation on the bearing of the ball mills can be used as reference by similar enterprises.