The WSP (Wheel Slide Protection) System has a critical role to confirm safe braking performance and prevent train accident from flatting of wheels in high speed train. Generally the braking forces should be lowered than maximum adhesion limit to secure rolling motion of wheels and prevent skid motion of those. However during the operation of high speed train, the presence of low adhesion between wheels and rails are very frequent due to eniviromental factors such as rain, snow and leaves. Thus the WSP system controls the pneumatic pressure in brake caliper by the electronic valves to adjust braking force in low adhesion condition. In this paper we present dynamic modeling of braking system and simulation results for high speed train. And the effect of reference speed for WSP control is also evaluated.