The invention discloses an air source heat pump device with a solar hot water auxiliary defrosting function and a use method thereof. The device comprises a solar hot water system and an air source heat pump system, wherein the solar hot water system comprises a circulating water pump, a solar hot water drain pipe, a first cutoff valve, a solar heat collector, a heat storage water tank and a third cutoff valve, and the air source heat pump system comprises an evaporator, an expansion valve, a condenser, a four-way reversing valve and a compressor. The exterior of the original evaporator of the air source heat pump device is additionally provided with one row of heat exchange pipes, and hot water heated by solar energy flows in the heat exchange pipes. On one hand, the hot water is used for preheating the air, and on the other hand, a refrigerant pipeline is heated through the heat conduction of fins, so the evaporation temperature is raised to fundamentally avoid frosting. The air source heat pump device and the use method have the advantage that the evaporation temperature is raised to fundamentally avoid frosting; meanwhile, the efficiency and the working stability of the heat pump are improved, the electricity is saved, the environment-friendly and energy-saving effects are realized, and the like.