Under the background of the dual-carbon goal and the reform of the electricity market, it is of great significance to study the economic scheduling method of the electric vehicle charging system to promote the rapid development of the electric vehicle and the charging system and guide the friendly interaction between the electric vehicle and the power grid. Based on the model predictive control theory, this paper establishes the dispatch process of electric vehicle charging system in the power market, which mainly includes four parts: model input, electricity price prediction, economic dispatch and rolling update. The economic dispatch model of the charging system is the core of the dispatch process. With the lowest cost of the charging system as the goal, the charging plan of each charging pile in the future period is solved and the charging plan for the next period is actually implemented. Among them, the Mas first law in the economic dispatch model is a nonlinear constraint in the form of square root, which can be converted into a multi-segment linear constraint to improve the computational efficiency of the economic dispatch model. Finally, an example verifies the feasibility and effectiveness of the economic dispatch method of charging system based on model predictive control.