Abstract: Braking deceleration accuracy and velocity accuracy are two important indexes to measure the brake system performance. However, in real braking, the deceleration cannot be accurately measured because that it is easily affected by the line conditions and brake shoe coefficient. Conventional closed-loop control method cannot deal with the phenomena of input delay and nonlinearity in the system. According to the operation principle of the electro-pneumatic brake system, a nonlinear brake model with input delay is built. To deal with the nonlinearity, input delay and bounded disturbances in the system, a robust brake controller based on backstepping technique and Krasovskii functional operators is designed. By Lyapunov-Krasovskii method, the close-loop system is proved to be Input-State-Stable (ISS) with respect to bounded disturbances. To validate correctness of the robust controller, the brake model is simulated on Matlab. Results demonstrate that the proposed model not only improves the brake system performance, but also is robust to disturbances and input delay in the brake system.