The traditional potassium permanganate consumption (COD) test method is the detection method which has been widely used for many years. It has been applied to the detection of food contact materials and its products because it has some advantages, such as experimental operation, simple experimental principle and low experimental cost. But when dealing with a large number of samples, the traditional COD test method seems to be not very well. The traditional COD test method has some big disadvantages, such as low detection efficiency and high manpower cost investment. Therefore, some COD automatic titrators based on potentiometric titration technology have been invented in recent years. However, this type of COD automatic titrator is fundamentally different from the traditional COD test method in principle. The COD automatic measuring instrument based on color recognition technology can replace manual work while maintaining the same principle with the traditional COD test method, meeting the test requirements on technical indicators, realizing automation and improving the detection efficiency. This paper introduces a kind of COD automatic measuring instrument based on color recognition technology, and improves and optimizes the automatic titrator by experimental data.