This standard specifies the technical requirements, performance indicators and detection methods of hexavalent chromium water quality automatic online monitor, which is suitable for its production design, application selection and performance detection. The range of the instrument should be 0.010~ 2.00 mg/L, which is mainly used for the monitoring of surface water, domestic sewage and industrial wastewater. A series of normative documents are cited, including the determination method of hexavalent chromium water quality, the protection level of the shell, and the data transmission standard of the online monitoring system for pollutants. The terms and definitions cover error of indication, lower limit of quantification, precision, zero drift and range drift, etc.