In this paper, an adaptive control scheme is designed for the regenerative brake of a hybrid electric bus. The estimated brake torque coefficient is used to produce the input of regenerative braking system. When the brake fade of friction brake happens during a normal brake process, the regenerative brake torque can work as the compensation. Simulations of realistic test scenario with a longitudinal vehicle model are used to validate the proposed control method. The results indicate that the developed regenerative brake control law can provide the hybrid electric bus with an optimised comfort during a normal brake process.