The disadvantage of the numerical implementation of conventional Preisach model for describing piezoelectric hysteresis is analyzed in the paper. For the deficiency of the wiping out property in the conventional numerical implementation, an improved numerical implementation of Preisach model with wiping out property is proposed and its detailed principal and implementation procedure is presented. The related experiments are carried out and the result demonstrate that, compared with the conventional numerical implementation, the proposed numerical implementation can calculate the output displacement of piezoelectric actuator more accurately in complicated loading procedure and could be extensively applied.