Abstract:It was compared from the metrological performance requirements, verification method, condition, identification items, verification equipment and technical parameter for verification about the difference between On-line Automatic Determinators of Chemical Oxygen Demand(COD) JJG1012-2006 and JJG1012-2019, and the reason of changes was given. It had a detailed interpretation of the new regulation. Compared with the old verification regulation, the new regulation was more suitable for requirements of metrological verification.