The utility model discloses a cold and hot water supply water source heat pump unit. The water source heat pump unit comprises a closed refrigeration cycle system and a hot water supply system. The closed refrigeration cycle system and the hot water supply system are connected through a pipeline, so that air conditioning cold (hot) water and domestic hot water can be supplied simultaneously, cold and hot water balance can be realized by adjusting the flow of cooling water and the domestic hot water, overhigh condensing temperature is avoided, winter and summer modes can be switched only through conversion of a three-way valve, and the water source heat pump unit is easy and convenient to control.