The invention provides a braking system used for a driverless vehicle and capable of switching driving modes. Through mutual detecting of two driving steering engines, operating states of two brakingsystems are detected in real time, and when one of the driving steering engines is abnormal, the other driving steering engine triggers the emergency braking mode; and through design of a pushing block I and a connecting rod at the outer edge of an output shaft of a steering engine and a pushing block II in a matching hole of the output shaft, one-way transmitting of torque in the braking processis achieved, that is, the torque only can be output through a braking steering engine, torque from the connecting rod to the braking steering engine cannot be transmitted, and thus a driver can manually step on a pedal to brake.