Abstract: To improve the reality of virtual environment,a real-time pedestrian simulation model based on fluid dynamics is implemented by taking a pedestrian flow as a water flow.By numerically solving the Navier-Stokes equations which describe 2D incompressible fluid,a velocity field which is used to drive the movements of pedestrians is obtained.To render thousands of agents in real time,a LOD hierarchical model is employed to balance between computational time and rendering quality.Switch between detailed mesh models and impostor images are automatically realized according to the distance between agents and viewpoint.Experimental results demonstrate that the proposed approach can simulate real-time flow-like pedestrians efficiently.