The district cooling system is a special and large-scale category of central air conditioning load with the potential to participate in the power system frequency regulation. Based on the model prediction control method, a control strategy for the district cooling system is proposed to participate in secondary frequency regulation. First, the dynamic model of district cooling system and the dynamic model of thermal power system frequency regulation are established. Then, with the goal of minimizing the deviation between building temperature and human comfort temperature, thermal power unit frequency regulation commands and the frequency deviation, the model predictive controller is designed to optimally allocate the frequency regulation commands of the district cooling system and thermal power units. Finally, simulations were performed on a 10-unit 39-node system containing district cooling system, and the results show that the participation of district cooling system in frequency regulation can improve the system frequency regulation effect and the participation in frequency regulation does not have a large impact on the user comfort level.