Measuring device for material concentration

The utility model relates to a measuring device for material concentration. The measuring device for the material concentration is used for measuring the concentration of a material to be measured in a water sample. The measuring device comprises colorimetric tubes used for filling the water sample to be measured and one or more groups of light detection devices which are installed at the two sides of the colorimetric tube respectively. Each light detection device comprises a light source exiting module and a light source receiving module. The optical lengths of the colorimetric tubes are different. Different groups of light detection devices penetrate through in the different light length positions of the colorimetric tubes. A double optical length design is adopted, selective measurement is conducted according to the difference of absorbancy spans of materials contained in different measuring liquids, the consumption of the water sample and reagent can be reduced, and the amount of waste liquid is reduced; double wavelength is adopted to conduct comparison measurement, and the disturbance of the water sample can be eliminated. The measuring device for the material concentration has the advantages that accurate measurement can be conducted on a monitoring factor with a small absorbancy span or the water sample with low concentration, the disturbance can be eliminated effectively when the measurement is conducted, and the precision of the measurement can be improved.