The mixed absorption refrigeration cycle which was suitable for the solar air-conditioning was presented. On the base of characters of working process, the models of each component were established in the paper. The universal module of thermo-physical properties of LiBr solution and water was written, control flow graph of program was given and simulation program of the mixed absorption refrigeration system was developed. The simulation results showed that the relations between LiBr solution concentrations and performance of mixed absorption system. The simulation program provided theoretical rules of optimization designs for commercial solar absorption air-conditioning.