The invention relates to a heat-pump based all-purpose sea water desalination system. The heat-pump based all-purpose sea water desalination system comprises a compressor, a sea water heating desalinating device, a finned dual-use evaporator, an electronic expansion valve, a supercooling intercooling device and a turbocharger; the sea water heating desalinating device comprises an evaporative condenser, a finned evaporator, a vacuum pump, a condenser water pump, a spraying system, a sea water tank and a fresh water tank; and the finned dual-use evaporator comprises a finned coil, a heat absorbing fan, an evaporator sea water pump, the spraying system and the sea water tank. If the temperature is relatively high in summer, and the temperature of the sea water is relatively lower than the local temperature, the finned dual-use evaporator is used as an air source heat pump to heat to prepare fresh water; if the temperature is relatively low in winter, and the temperature of the sea water is higher than the local temperature, the finned dual-use evaporator is used as the sea water source heat pump to heat to prepare the fresh water, and the boiling point of the sea water is reduced by utilizing the vacuum pump. The heat-pump based all-purpose sea water desalination system is low in equipment investment, realizes energy conservation and emission reduction, and stably and reliable runs.