The invention provides a braking method and system under vehicle sliding. The braking method comprises the following steps that the reference speed of a vehicle and the shaft deceleration of each shaft are calculated according to the shaft speed of each shaft through a braking control unit; the current sliding state of each shaft is determined according to the difference between the reference speed and the shaft speed of each shaft and the shaft deceleration of each shaft through the braking control unit; whether electric braking removing conditions of the vehicle are met or not is judged according to the vehicle speed, the reference speed, the shaft speeds, the difference between the reference speed and the shaft speed of each shaft and the maximum value of corresponding electric braking reducing numeric value of the current sliding state of each shaft through the braking control unit; if the electric braking removing conditions of the vehicle are met, the braking control unit sends an electric braking removing signal to a traction control unit; and the traction control unit removes electric braking according to the electric braking removing signal. According to the braking method, vehicle electric braking can be removed timely when the vehicle slides seriously, and a wheelset abrading accident is avoided.