Using price signal and an incentive mechanism, Demand Response (DR) is an important measure to ensure the safe, reliable, and economic operation of a power system. The incentive effect of traditional price incentive is the same in all periods, resulting in insufficient prediction accuracy in any particular period. In this paper, the Price Elasticity Matrix of Demand (PEMD) is studied, and an improved price elasticity matrix model based on the weight of the elasticity effect is proposed. The advantage of the model is that it can unify the rigid load and the flexible load, and set the weight for the price impact of different periods on other periods. The structure and calculation method of the price elasticity matrix determined by the price policy and load type is proposed. Finally, the effectiveness of the model is verified by simulation. The results show that the method can reduce peak power consumption by 4.23% and increase valley value power consumption by 4.86%. This work is supported by the International Science and Technology Cooperation Program of China (No. 2018YFE0125300) and Science-Technology Innovation Platform and Talents Program of Hunan Province (No. 2019TP1053).