This standard specifies the technical requirements, performance indicators and detection methods of ammonia nitrogen water quality online automatic monitor, which is suitable for the monitoring of groundwater, surface water, domestic sewage and industrial wastewater. The range of the instrument should be 0.1~ 150 mg/L, which can meet various water quality monitoring needs. A series of normative documents are cited, including general principles of industrial product instruction manuals, data transmission standards for pollutants online monitoring system, determination methods of ammonia nitrogen in water quality, etc. Terms and definitions include basic detection range, extended detection range, sample, error of indication, lower limit of quantification, etc.