Abstract: For a large-sized hollow rotary often used in factories,a suitable dynamic balance device is sometimes not available or it isnot appropriate to use the dynamic balance device so it is aftenrectified on the working sites with hands. Due to lack of thetheoretical analysis and aneffective method, the dynamic unbalance rectifying is doneinefficiently. This paper makes some theoreticalanalysis and puts forward an efficient dynamic balance method. It isshown that this method is effective.