In range of high pressure, the performance of two stage compression cycle with an expander (TSCE+IC) is better than the two stage cycle with an intercooler (TSCC+IC). In the cycle (TSCE+IC), the optimum discharge temperature is 42°C and the highest COP is 3.3, in the cycle (TSCC+IC), the optimum discharge temperature is 50°C and the highest COP is 3.07. In the cycle (TSCC+IC), the optimum intermediate pressure is 5.8MPa and the highest COP is 3.08, in the cycle (TSCE+IC), the optimum intermediate pressure is 6.2MPa and the highest COP is 3.33. With increasing of evaporating temperature or decreasing outlet temperature of gas cooler, the performance of cycle (TSCE+IC) or cycle (TSCC+IC) is an increasing trend. Under the same conditions, expander cycle performance superior to the throttle valve performance. Some fundamental data were obtained for improving cycle performance and developing the products of CO2 refrigeration air condition and heat pumps.