In order to provide a reliable approximate vehicle velocityd for simulating a vehicle-pedestrian accident,the relationship between the flight-phase distance of pedestrian and the vehicle velocity is derived,based on theclassical mechanics and some hypotheses.Then,two useful prediction models of minimal vehicle velocity are ob-tained,and one of them is used for a flat road while the other is used for a slope.Moreover,the two models are ver-ified by comparing the existing researches with the simulation results obtained through Pc-Crash.It is found that thetwo models are effective and feasible.Finally,the two models are further verified by a real vehicle-pedestrian acci-dent.