JJF 1565-2016 "Specification for calibrating heavy metals water quality online analyzer" is suitable for calibrating heavy metals such as lead, cadmium, mercury, arsenic, chromium, copper, zinc, nickel, iron, manganese and other heavy metals. This standard specifies two main Measuring methods: Spectrophotometric method, spectrophotometry and anode stripping voltammetry. Spectrophotometric method, spectrophotometry determines the content of heavy metals by measuring the Absorbance value at a specific wavelength; anode stripping voltammetry uses the principle of electrolysis to achieve enrichment and dissolution of heavy metals ions. The instruments are classified into Type I and Type II, which are suitable for monitoring different water quality such as surface water, groundwater, drinking water and domestic sewage, industrial wastewater, etc. The standard details the composition of the instrument and terms such as Memory effecy, which are designed to ensure its accuracy and Reliability to meet the needs of environment monitoring and water quality management.