Aiming at the problem of anti-rolling control of overhead cranes under the influence of external disturbance and uncertain system parameters, a terminal sliding mode control method based on disturbance observer is proposed. In this method, the crane dynamics model is established on the premise of retaining the external disturbance term. Then, the disturbance observer is designed to estimate the disturbance suffered by the system. Based on the estimated value, an adaptive terminal sliding mode controller is designed to actively compensate for the influence of external disturbance on the system. The accurate positioning of the trolley is realized and the load swing is effectively suppressed. The simulation results show that the method has good control performance and makes the system robust against external disturbance.