Seawater treatment system and seawater treatment method

The invention belongs to the technical field of seawater treatment, discloses a seawater treatment system and a seawater treatment method, and solves the technical problem of low seawater resource utilization degree in the prior art. The seawater treatment system comprises a filtering device used for removing solid particle impurities in seawater and outputting filtered produced water; the nanofiltration device is used for separating and filtering monovalent ions and multivalent ions in the produced water and outputting nanofiltration produced water and nanofiltration concentrated water; the softening device is used for removing multivalent ions in the nanofiltration concentrated water and outputting softened produced water; the electrolytic hydrogen production device is used for decomposing organic matters in the nanofiltration produced water, producing hydrogen and outputting electrolytic produced water; the desalting device is used for separating salt and fresh water in the electrolyzed water; anodes and c