Water quality index prediction model construction method and water quality index monitoring method

The invention relates to the field of environmental monitoring and provides a water quality index prediction model construction method and a water quality index monitoring method, thereby solving a problem of the large error in water quality COD index monitoring according to the existing spectroscopy. The water quality index prediction model construction method comprises: collecting a plurality ofwater samples as water samples and acquiring required water quality indicators of all water samples; for each water sample, measuring a corresponding spectrum to obtain an original spectrum and acquiring physical parameters; carrying out digestion on the water samples at least twice, measuring a corresponding spectrum once every digestion to obtain all digestion spectrums, and acquiring a digestion parameter of every digestion as well as the physical parameters of the water sample after each digestion; and according to the data collected by all water samples, constructing all water quality indicator prediction models