The invention provides a low-temperature heat pump system and a control method of a reversing valve of the low-temperature heat pump system, and belongs to the technical field of refrigeration air conditioners and low temperature heat pumps. The problems of unreasonable design and the like in the prior art are solved. The low-temperature heat pump system and the control method of the reversing valve of the low-temperature heat pump system comprise a compressor, an air heat exchanger arranged in an outer chamber, a water-side heat exchanger arranged in a room, a throttling device and a liquid storage device, wherein the compressor, the air heat exchanger and the water-side heat exchanger are connected through a refrigerant pipeline, the throttling device and the liquid storage device are arranged between the air heat exchanger and the water-side heat exchanger; a refrigerant inlet end on the compressor, a refrigerant outlet end on the compressor, a refrigerant port on the air heat exchanger and a refrigerant port on the water-side heat exchanger are connected with a S-end, a D-end, a C-end and a E-end in a one-to-one mode of the reversing valve respectively. The low-temperature heatpump system and the control method of the reversing valve of the low-temperature heat pump system have the advantages that whether the air reversing valve in the system is reversed in place or not isjudged by detecting the comparison situation of the air suction temperature and the heat source side temperature, so that the use experience of the user is prevented from being severely influenced bythe fact that an internally-arranged protector of the compressor is cut off.