Abstract: Based on the air source phase change energy storage cascade heat pump heating system,two typical weather conditions of sunny,rainy and snow weather are selected to collect experimental data for each part of the heat pump and energy storage. The theoretical calculation and experimental analysis show that when the system is sunny in winter,the system COP is obviously higher than the rainy and snowy weather conditions. Under the extreme weather conditions,the heat pump consumes slowly as the outdoor ambient temperature gradually increases,and as the ambient temperature decreases. The heat pump power consumption is on the rise;the research results show that the higher evaporation temperature and lower condensation temperature make the heat pump cycle COP value at a higher level,so the system can still operate efficiently and stably under different working conditions.