Abstract: Aiming at the grid connection of a high-proportion renewable energy,this paper proposes a multi-objective day-ahead optimal dispatch model for a high-proportion new energy power system including wind power,photovoltaic,thermal power and pumped storage. This model considers the operating costs of thermal power units,pollutants penalties and renewable energy curtailment under new operating conditions such as deep peak shaving and frequent ramps of thermal power units. This model takes the lowest system operating costs,the largest wind power and photovoltaic output and the smallest net load fluctuations as the optimization goals,and uses the NSGA-Ⅱ algorithm to optimize the solution. Through the simulation calculation of different scheduling scenarios on a typical day,the results show that the calculation model of the total operating costs of the system established in this paper can take into account the economy,environmental protection and consumption of the system. The multi-objective optimization scheduling strategy proposed in this paper can promote the consumption of high proportion of renewable energy,alleviate the peak shaving pressure of thermal power units,reduce the total costs of system operation,guide the thermal power flexibility transformation of power system,and ensure the safe,stable and economic operation of power system.