Taking a site in Tianjin as the object， this paper carried out pollution identification， preliminary sampling and supplementary stratified monitoring， and constructed a preliminary site conceptual model， a pollution characterization conceptual model， and a groundwater flowsolute transport numerical model in sequence. The update and optimization of the conceptual model of the site intuitively connects the spatial distribution of pollution and the stratigraphic structure， and clarifies the causes of pollution. The results indicate that the site is mainly polluted by chlorinated hydrocarbons， and the pollution spreads around from independent pollution sources， and mostly accumulates in shallow diving， and the silty clay layer effectively blocks its vertical migration. The numerical model pollution prediction showed that the pollutant content decreased with time， and the convection dispersion had little effect on it. The method of combining the conceptual model of the site with the numerical model based on the accurate survey provides a working basis for grasping the actual pollution of the site and later decisionmaking.