The ideal braking force distribution curve between the front and rear wheels of vehicle was modified in order to be applied in the vehicle with eddy current retarder. Based on the qualitative analysis of the vehicle braking stability, the present work puts forward a method to improve the braking stability of vehicle equipped with retarder by increasing the braking force distribution ratio between the front and rear brakes. The quantitative computation of given vehicle shows that the method can enlarge the range of synchronized adhesive coefficients, reduce the flexibility of being locked first of rear wheels and improve the braking stability.