Taking the honeycomb paperboard mould for example, the sensitivity analysis and structural optimization are studied under Pro/MECHANICA. Three-dimensional model of honeycomb paperboard mould is built. The important design parameters are determined by the structure of punch static analysis and sensitivity analysis. Taking minimum stress, strain and minimum deformation as the target function, the structural optimization of punch is finished. Study shows that this method can solute the fatigue failures of the honeycomb paperboard mould effectively and enhance efficiency of optimal design.