The invention discloses a bidirectional vapor compression continuous flash evaporation sea water desalination method and a bidirectional vapor compression continuous flash evaporation sea water desalination device, which are used for the field of sea water desalination. Particularly, a motor is used for driving a vapor compression piston plate of a large-sized vapor compression cabin to do reciprocating motion and perform bidirectional vapor compression, so that vapor which is formed in an approximately vacuum space in a sea water closed system by means of gravity and atmospheric pressure is continuously guided into an approximately vacuum space or low-hydraulic-pressure fresh water which is formed in a fresh water closed system by means of gravity and atmospheric pressure to obtain freshwater; when the fresh water flows through a ribbon-shaped fresh water flow guide pipe which is spirally coiled in the sea water evaporation cabin and a sea water supply pipe, is alternately and gradually screwed outwards and inwards and is gradually screwed downwards, the preheated sea water is further heated; the motor is simultaneously used for driving a heat exchange agent to circularly flow in a closed circulating space; the sea water is further heated by using heat discharged by vapor liquefaction and motor operation to promote evaporation; and the low-energy-consumption fresh water massproduction method and the low-energy-consumption fresh water mass production device in which automatic sea water supply and automatic fresh water export are utilized and non-natural energy is consumed by one motor and one piece of low-temperature preheating equipment are realized by means of natural power.