Abstract: A non-linear dynamic model is set up for high-speed passenger car considering total track stiffness and damping. Based on the first order ODE approximation theory and the Hopf bifurcation theory, the Hopf bifurcation speeds for high-speed passenger car on line and curved tracks are studied. The DEPAR continuation algorithm is adopted to determine the equilibrium positions of vehicle system on curved tracks. The effects of curve radius, superelevation of the track and suspension parameters of the bogie on the vehicle's Hopf bifurcation speed are investigated. Results show that the larger curve radius and super-elevation of the track, the higher Hopf bifurcation speed. The Hopf bifurcation speed for high-speed passenger car on elastic track is higher than that on stiff track. The effect of bogie suspension parameter on vehicle's Hopf bifurcation speed on stiff track is the same as that on elastic track.