Loadest model is a software for estimating River component load. The estimation of pollutant flux is a simple method to master the river transport load, which can provide a scientific basis for the total amount control of river basin. Based on the continuous water quantity data and discrete water quality data, the pollutant flux regression equation is established to estimate the pollutant flux under different time scales (day / month / season / year). In addition, the model also considers the situation of censored water quality data, It is an effective way to estimate the pollutant flux of low frequency water quality monitoring river