In view of the problem that there is no suitable heat source for heating in winter in the mountainous areas of northern China, in this paper, based on the principle of solidification and heat exchange of water-ice phase change, the latent heat of solidification of water phase change is used as the low-temperature heat source of heat pump unit, and the phase change energy plus heat pump heating system is designed and developed and experimentally studied. The results show that when the icing thickness reaches 30 mm in the solidification and heat exchange stage of the system, the comprehensive heat transfer coefficient is 151 W/(m²· K), and the Coefficient of Performance (COP) is 3.52. The design cycle is 4 h and the heat transfer coefficient is 150 W/(m²· K), in order to determine the energy storage capacity and heat transfer of the U-shaped ice storage tank. The energy consumption of ice melting accounts for 5.6%, and the ice melting time is 26 min. The experimental system can meet the heating needs of a house of 210 m².