Because of the large inertia of a synchronous generator, conventional centralized load frequency control is not fast enough. Controllable load resources with fast response capability on the user side provide new opportunities for system frequency regulation. In this paper, the load frequency control of a multi-area interconnected power system with controllable load regulation capability is studied. Load frequency response and automatic generation control models of a multi-area interconnected power system with controllable load are established. Based on a continuous time domain alternating direction multiplier algorithm and the distributed model predictive control method, a distributed model predictive optimal load frequency control model of a multi-area interconnected power system with controllable load participation is proposed. Simulation is carried out based on the modified three-area IEEE39 bus system, illustrating that the proposed model can significantly reduce the time required for the system to return to a steady state. The control freedom of the distributed control strategy is higher, and this enhances the controllability of the system.