Groundwater is the main source of water supply in many cities of China, and it has been polluted in different degrees, leading to intense contradiction between the supply and the demand of groundwater resources. The research status and problems of the early-warning method of groundwater pollution were analyzed in this paper, the groundwater pollution early-warning method based on a numerical model was studied in a chromium residue site in northern China, and different early-warning grades were zoned by the model. The result of the study provides scientific basis for regional groundwater pollution prevention and control planning.