This instrument can quickly and accurately measure chromaticity indicators in surface water, groundwater, urban sewage, and industrial wastewater, with direct reading of concentration; It can be widely used in sectors such as water plants, food, chemical, metallurgical, environmental protection, and pharmaceutical industries. The instrument is composed of a single spectrophotometer with a fixed wavelength and a fixed purpose. It uses the principle of spectrophotometry to measure various parameters, and establishes a linear curve between the concentration color development and absorbance of different parameters in the instrument. The instrument determines the concentration of the tested water sample by identifying the color. This instrument adopts a fully Chinese menu, which is easy to operate, convenient to use, and has high measurement accuracy.