The invention discloses a heat pump air conditioner based on phase change energy storage and a domestic hot water association system. Stored energy of two phase change materials in different temperature sections is used for coupling the heat pump air conditioner and solar hot water. The association system comprises a heat pump air conditioner unit, a phase change energy storage unit and a solar hot water unit; the heat pump air conditioner unit includes a compressor, a condenser, an expansion valve, an evaporator and a heat exchanger; the phase change energy storage unit includes a high-temperature phase change chamber, a low-temperature phase change chamber, a thermal insulation layer and an access port switching pipeline; and the solar hot water unit includes a solar heat collector, an electric auxiliary heater and a water tank. The system supplies cold in summer and heat in winter, is applied to places needing domestic hot water all year round, realizes transfer of the energy generated by the heat pump air conditioner unit on time through synchronous energy storage and energy release for high temperature and low temperature in the phase change energy storage unit, achieves the purpose of clipping peak to fill valley on the power consumption, and realizes transfer of the energy generated by the heat pump air conditioner unit and the solar hot water unit on time and space.