The invention relates to the field of vehicle engineering and discloses an electric power-assisted braking system with composite functions. The electric power-assisted braking system comprises a brake pedal displacement sensor, a brake pedal, a pedal travel simulator, an electric power-assisted assembly, a main cylinder, a wheel cylinder, a hydraulic control unit, a liquid storage tank, a motor, a deceleration and torque increment mechanism, an electronic control unit, a normally open electromagnetic valve, a normally closed electromagnetic valve and a vehicle-mounted other sensor. By designing the pedal travel simulator, decoupling of friction braking force and regenerated braking force can be achieved, and continuous variable crural feeling is provided; a motor assisting device, a brake anti-lock system and the hydraulic control unit can be integrated, and an active braking function is achieved; and no interference exits between motor input and driver input, active braking can be achieved through the motor, and the electric power-assisted braking system can serve as a brake actuating mechanism of intelligent automobiles and unmanned automobiles.