Abstract: A mathematics model forecasting the impacts of river wastewater unsaturated filtration on its offshore soil and groundwater quality is established based on the analysis of the river wastewater unsaturated filtration and the transportation mechanism.The implicit difference method and the time-center difference formats are performed in the disperse equations,which have obtained good effects.The conservative pollutant Cl^- and non-conservative pollutant nitrite of river wastewater are taken as examples to study the model parameters of the transportation and transformation of the unsaturated filtration pollutants in the soil and groundwater.Finally the model is verified by the field data of Xucun and Huangqiao's cross sections in Xuzhou,Jiangsu province.The result shows that the calculated data agrees with the measured data.