GB/T 11913-1989 is a water quality testing standard. Electrochemistry probe method is used to determine dissolved oxygen in water. Dissolved oxygen is a key indicator to measure water quality, which affects the survival of aquatic organisms and the self-purification ability of water bodies. The standard specifies the type and operation steps of electrochemistry probe in detail, including probe calibrating, water sample measurement and result calculation. The method is simple to operate, fast in Response, and can be measured in real time. It is suitable for a variety of water bodies, providing reliable data for water quality monitoring, water ecological research and related environmental protection work, and helping to maintain a healthy water ecological environment.