During the production of ultrapure water, the degradation of TOC (total organic carbon) is very important. The ultraviolet technology with UV-C band 185nm wavelength low-pressure high-energy, combined with UV-C254nm ultraviolet sterilizer, is catalyzed by high UV-185 ultraviolet light. The hydroxyl radical are generated in the water, and the organic matter is oxidized and degraded to achieve the controlled amount of TOC in the water.