Seawater freezing desalination system and method utilizing LNG cold energy

The invention provides a seawater freezing desalination system and method utilizing LNG cold energy. The seawater freezing desalination system comprises an LNG vaporizer, a refrigerant storage tank, a subcooler, an ice storage tank, an ice crystal eliminator, an ice-water separator, an ice crystal washing tower, an ice melting device and a concentrated seawater heat exchanger. Firstly, LNG exchanges heat with a refrigerant and is gasified, pre-cooled seawater is further cooled in the subcooler after the refrigerant exchanges heat and is cooled to become supercooled water, the supercooled water enters the ice storage tank to generate ice slurry, the ice slurry sequentially enters the ice-water separator and the ice crystal washing tower, washed and desalted ice crystals are heated and melted into freshwater by the seawater in the ice melting device, and meanwhile, feeding seawater is pre-cooled. The low-cost LNG cold energy is used as a cold source required by the process, the ice slurry is prepared by adoptin