Seawater desalination and salt separation system and method

The invention discloses a seawater desalination and salt separation system and a seawater desalination and salt separation method. The device has the advantages that the concentration and salt separation unit is combined with the crystallization unit, so that concentrated water generated after concentration and salt separation enters the crystallization unit, industrial salt is prepared, seawater resource utilization and zero-emission treatment are realized, no concentrated water returns to the sea, and the ocean water environment is protected; monovalent salt and divalent salt can be separated through a nanofiltration membrane device, and sodium chloride and potassium chloride in the monovalent salt can be separated through evaporative crystallization and freezing crystallization, so that inorganic salt contained in seawater is separated out in the form of crystals of sodium chloride, sodium sulfate and potassium chloride, and is used as an industrial raw material for resource utilization; after reverse osmo