The utility model relates to an air source heat pump. Air source heat pump includes: the compressor, the main condenser and the main evaporimeter that link to each other with the compressor, with the vice evaporimeter and the vice condenser of the whole preparation of main evaporimeter, the air inlet of compressor is connected to the export of vice evaporimeter and the export of main evaporimeter and carried forward, and the import of vice evaporimeter is continuous with the export of vice condenser, and the import of vice condenser is continuous with the export of main condenser. Compare with the air source heat pump of traditional refrigerants such as use R22, the utility model discloses an increasing vice condenser and vice evaporimeter, making the complete condensate of non - of condenser export get into the complete condensate of pair condenser further condensation becoming, it is gaseous that the condensate gets into vice evaporimeter systematic heat altered one -tenth low temperature completely, and low temperature gas is got into by compressor inlet and is compressor make -up gas to reduce exhaust temperature, make air source heat pump can 25 normal operating among DEG C low temperature environment, the leaving water temperature can reach more than 50 DEG C.