Abstract: Chromium pollution has become one of the heavy metal pollutions in soil and groundwater. To study the migration law of chromium (Cr) in the groundwater of contaminated sites and analyze and predict the time for hexavalent chromium to migrate to the water source protection area, a certain chromium-contaminated site in Xinxiang City, Henan Province was taken as the research area. The grounder modeling systems (GMS) software was used to establish the numerical simulation model of groundwater flow and the solute transport model to analyze and predict the migration of hexavalent chromium without considering adsorption and with adsorption considered. The conclusions show that without considering adsorption, the time for Cr(Ⅵ) in the shallow phreatic aquifer to migrate to the water source protection area is 78 years, and in the deep phreatic aquifer, it is 70 years. When adsorption is considered and the Langmuir adsorption model is adopted, the time for hexavalent chromium in both the shallow and deep phreatic aquifers to migrate to the water source protection area is about 4 years slower than that without considering adsorption. In addition, under the condition of considering adsorption, the scenarios of three changes in the source concentration, namely continuous release of the pollution source, disappearance of the pollution source after 10 years, and continuous attenuation of the pollution source, were simulated. The simulation results are as follows: In the early stage, the original concentration of Cr(Ⅵ) in the groundwater rapidly rises to a peak and then drops rapidly. When the chromium slag pile infiltrates again after leaching in the later stage, the concentration changes of Cr(Ⅵ) under the three scenarios show differences. When the pollution source is continuously released, the concentration slowly increases; when the pollution source disappears after 10 years, the concentrations at the two observation points first slightly increase and then gradually approach 0; when the pollution source continuously attenuates, the concentration first rises and then falls and finally approaches 0. At the same time, it can be obtained that shortening the distance between the pollution source and the observation point will significantly reduce the migration time of Cr(Ⅵ), and the time for it to reach the observation point is negatively correlated with the hydrodynamic conditions. This phenomenon is mainly controlled by key hydrogeological parameters such as the diffusion characteristics of the pollution plume and the permeability coefficient of the aquifer medium. The results of this study can provide a scientific basis for the prediction, prevention, and control of the chromium pollution range in contaminated sites.