Air source heat pump air conditioning systems are widely used in heating, hot water supply and drying,due to their advantages of high efficiency, energy saving and environmental protection. Researches on the circulation construction, defrosting mechanism and control strategy of the air conditioning system are made at home and abroad,and the advantages and disadvantages of the various technologies are analyzed. The typical application scenarios of air source heat pump air conditioning systems in different industries are introduced,and attention is paid to the contributions to "coal-to-electricity" projects in northern China made by the systems. The COP of the system can reach 2.13, which indicates a significant energy saving. Finally, the challenges faced by the promotion of air source heat pump air conditioners are illustrated, including deficient policy and low public acceptance. Corresponding improvement should be made on the components, cycles, defrosting and control mechanisms. Moreover, the further advancement for the system can made by integrating thermal storage, big data and artificial intelligence technologies, which will facilitate the realization of carbon peaking and carbon neutrality under the new situation.