The new (HJ 828—2017) and old (GB/T 11914—1988) version standard of Water QualityDetermination of the Chemical Oxygen DemandDichromate Method were compared and discussed. As compared with the old version, the sample volume, the addition amount of mercury sulfate, the method of chloride ion determination, the method determination limit, quality assurance and quality control were revised. The checkout test, the calculation of method determination limit and the problems exist in quality control of parallel sample in new version standard were discussed.