The invention relates to the technical field of electric vehicle braking, and particularly discloses a braking device with auxiliary assisting force. The braking device comprises a hydraulic braking force output module, a braking force input mechanical module, an auxiliary assisting force input module and a control module; the braking device is provided with a first cavity and a second cavity, a reset spring for adjusting the stroke clearance of pedals is arranged in the second chamber, and the second chamber is connected with a transfer sliding block in a sliding mode; and a push rod is provided with a spherical part, and the push rod and the transfer sliding block form a spherical hinge pair. The braking device with the auxiliary assisting force adopts the modular design, a vacuum pump, a vacuum tank and the like used by an existing braking device are canceled, the force directly acts on a braking main cylinder piston by a motor through a sliding bar, the response time is shortened, the reliability is improved, the noise is reduced, and the occupied space is reduced; in addition, two braking ways of pedal force of a driver and the motor are achieved, the uniformity with the installation way of the existing braking device is ensured, and the traditional operating habit modes of the driver are retained; and an electromagnetic clutch is arranged additionally, the motor is protected effectively, and the service life of the motor is prolonged.