The utility model discloses a heat pump type seawater desalting device which comprises a heat pump compressor, an evaporation/condensation machine and a seawater pre-heater, wherein a heat exchange pipe and a spaying pipe are arranged in a shell of the evaporation/condensation machine; a seawater supply pipe is connected to the seawater pre-heater; a seawater output pipe of the seawater pre-heater is connected to the spraying pipe; a spraying pump is connected in series with the seawater output pipe and used for dividing the seawater output pipe into a front seawater output pipe and a rear seawater output pipe; a steam outlet of the evaporation/condensation machine is connected to an air suction pipe of the heat pump compressor; an air exhaust pipe of the heat pump compressor is connected to an input end of the heat exchange pipe of the evaporation/condensation machine; an output end of the heat exchange pipe is connected to a fresh water pipe; the fresh water pipe penetrates through the seawater pre-heater; a fresh water pump is connected in series with a protrusion part; a salt water output pipe of the evaporation/condensation machine is connected to the front seawater output pipe; a mixed salt water pipe is connected to the rear seawater output pipe; the mixed salt water pipe penetrates through the seawater pre-heater. The heat pump type seawater desalting device is energy-saving and environmental friendly.