At present, China is comprehensively deepening the reform of the electric power system, and the power retail business will be liberalized on a large scale. While bringing dividends to the society, it will have a huge impact on the production and operation of power grid enterprises.Based on the qualitative analysis of the influence of power retail business liberalization on power grid enterprises, this paper introduces the system dynamics model to conduct quantitative research.According to the business process, seven sub-models of power retail business cost-revenue model, power transmission and distribution business revenus-cost model, power value-added service revenus-cost model, grid staff turnover model, cash flow model, demand-side response model, power retail and related business profit model are respectively established.Based on the relevant data of the 2018 annual report of the electric power market of some province, this paper analyzes the influence of the relevant indicators of the electric power grid through three scenarios, namely the change of the growth rate of marketized electric power, the change of the agent electric power of the electric power selling company and the change of the price difference between the purchase and sale of electric power.The study has important reference value for power grid enterprises to actively respond to the reform and carry out the evaluation of power system reform.