Abstract: A co-optimization method was proposed for capacity allocation and frequency control parameters of thermal power-energy storage system considering flexible, economical and environment friendly operation. Firstly, a coordinated control strategy was designed for primary frequency regulation of combined thermal power and energy storage based on automatic allocation of power-energy storage by low-pass filter and the self-recovery of energy storage state was considered. Subsequently, considering frequency control performance, operational cost and pollutant emission of the system, a co-optimization model was developed for capacity allocation and frequency control parameters of thermal power-energy storage system, and a solution method based on particle swarm algorithm was provided. Finally, simulation verification was performed using a specific thermal power-energy storage system as an example. Results show that the coordinated control strategy and the co-optimization method are effective.