Abstract: Assessment of groundwater vulnerability as an essential tool for protection and management of groundwater resources is widely used. This article uses a modified DRASTIC model, in which a groundwater flow model is used as a data supplier, to evaluate the vulnerability of the Beijing plain aquifer, and discuss the pros and cons of this new method. The results of this method and ordinary one are familiar in high-value and low-value regions. However, the new method is more competitive in calculating water table, hydraulic conductivity and mapping aquifer media. The groundwater-model-based way is more objective in describing the influence of the aquifer media on groundwater movement and the time-based water table is available. The parameters describing the aquifer media of a calibrate groundwater model is more precise than the statistics-based way. The values between the estimated regions are more smooth than the ordinary one, which is accordance with the continuity of hydrogeological conditions.