Basic causes of damaged die were found by analysing the failure features of previous die.And through the punching experiments with different clearances under the guidance of theoretical principle, the influence of die clearance on quality of the hole was obtained. A set of applicable clearances which could meet the punching quality requirement and decrease the die wear were gained by studying the relation between the clearance, burr, hole diameter, material,strength and thickness respectively. Finally, the punching effect and situation of mould were tested by the feature of euphotic belt.