The invention provides a rail vehicle starting control method and device. According to the relation between a speed value of the backward sliding speed of a rail vehicle and a rotating-speed difference value of a motor, a starting control method under two different work conditions is provided; when the speed value of the backward sliding speed of the rail vehicle is larger than the rotating-speed difference value of the motor, the motor is controlled to output electric braking torque which corresponds to the rotating-speed difference of the motor and has the direction the same with that of the backward sliding direction of the rail vehicle, so that the backward sliding speed of the rail vehicle is constantly reduced until the speed value of the backward sliding speed of the rail vehicle is smaller than the rotating-speed difference value of the motor; when the speed value of the backward sliding speed of the rail vehicle is smaller than the rotating-speed difference value of the motor, the motor is controlled to output traction torque which corresponds to the rotating-speed difference of the motor and has the direction opposite to the backward sliding direction of the rail vehicle, and accordingly, the backward sliding speed of the rail vehicle is constantly reduced until the rail vehicle stops backward sliding and is started normally. Stable start of the rail vehicle at different backward sliding speeds is realized.