With implementation of the Maximum Allowable Values of The Energy Consumption And Energy Efficiency Grade For Household Refrigerators（GB 12021.2—2015）, this study experimentally investigated the application of 21 kinds of microchannel heat exchangers (MPE) on domestic refrigerator system. The investigation was conducted from component to system, and heat exchanger performance was compared with original condenser. The results show that for the best MPE sample, the heat transfer performance can increase by 13%, the air-side pressure drop is only 28%, and the refrigerant-side pressure drop is only 54%. The best MPE sample was introduced into a refrigerator system, and the charge of refrigerant for the system was optimized. The optimized system energy consumption was tested under national standard GB/T8059. The results show that the energy consumption of the new system was 2.8% lower than the original under a test condition of 25 ℃, and the calculated energy consumption based on the new national standard was 2.6% lower than the original. This can meet the first-class requirements of the new national standard.