Wall-mounted heat pump water heater

The utility model relates to a wall-mounted heat pump water heater which comprises an outer shell, a hanging plate arranged on the outer shell, a CO2 heat pump system, a phase change heat exchanger and a water tank, wherein the CO2 heat pump system, the phase change heat exchanger and the water tank are arranged in the outer shell. The CO2 heat pump system comprises a compressor, a plate heat exchanger, a throttling element and an evaporator, a first refrigerant flow channel and a first heat exchange flow channel are arranged in the plate heat exchanger, and the compressor, the first refrigerant flow channel, the throttling element and the evaporator are sequentially connected through pipelines to form a refrigerant loop; a first water inlet and a first water outlet are formed in the shell, a second water inlet communicated with the first water inlet and a second water outlet communicated with the first water outlet are formed in the water tank, and the water tank is communicated with the first heat exchange