The system takes reverse osmosis desalting technology as the core process and multi-media filter, activated carbon filter and softening filter as the pre-treatment to ensure that the inlet water quality meets the operating conditions of the reverse osmosis system. Ultraviolet sterilization, pasteurization, ozone sterilization and other sterilization processes sterilize purified water, system pipes and purified water storage tanks to ensure that the effluent water quality meets the requirements o