With the rapid development of society and economy, the groundwater pollution problem has become increasingly prominent, the pollution of Cr (VI) of the groundwater has become dangerous substances that harm environment and human health. Because of Cr (VI)''s highly toxic, easy migration characteristics, it brings a serious security risk to the groundwater environment.A three dimensional unsteady groundwater flow model of quaternary groundwater system was built based on the analysis of hydrogeological conditions of a city. All the parameters were determined by Visual Modflow of the model using 2005''s data; The reliability of the model was tested by 2005-2009''s data. The paper used the model to carry on groundwater flow field simulation and prediction, use the status quo of Cr (VI) pollution halo(2010) and prediction of groundwater flow field morphology superimposed to predict the development trend of the Cr (VI) pollution , Has important significance for local government departments to respond to Cr (VI) contaminated groundwater governance to provide policy recommendations and decision-making reference.