Abstract: A stochastic model predictive control(SMPC) algorithm based on Markov chain was proposed to improve the energy efficiency of the AC(air-conditioning) system. Due to the significant influence of heat load disturbance on the temperature performance and energy efficiency of AC system,the dynamics of the refrigeration cycle and cabin heat load was modeled based on the moving-boundary and lumped parameter method in this paper,and the heat load information was incorporated into the control model of AC system. Then,adopting the Markov chain algorithm to predict the disturbance of heat load,a stochastic model predictive control algorithm was proposed. The simulation results show that the proposed algorithm can improve the temperature performance and energy efficiency of the AC system.