The invention discloses a cascade sliding-mode observer and an adhesion factor and derivative estimation method. The cascade sliding-mode observer comprises a load torque observer and a load torque derivative observer; firstly a dynamical model for the operational process of a heavy load locomotive is created, a state equation for an adhesion control system is created according to a motor torque balance equation, a scheme for estimating the adhesion factor by a load torque is proposed, then the cascade sliding-mode observer is designed, the stability of the cascade sliding-mode observer is proved with the help of a Lyapunov stability theory, and then a sliding mode variable structure equivalence control principle is utilized to create an algorithm for estimating the adhesion factor and a derivative. The direct differential computation of a signal is avoided, the derivative of the load torque is estimated according to the sliding mode variable structure equivalence principle, and a method for inhibiting the buffeting of the sliding-mode observer is provided; the algorithm is simple and easy to implement; an observation value and an actual value are matched through simulation and experiments, and the effectiveness of the algorithm is verified.