Abstract: In this study, the dynamic sliding mode controller of hydraulic turbine governing system is designed based on the sliding mode control method to address the chattering problem of hydraulic turbine governing system in sliding mode control. Firstly, a mathematical model of hydraulic turbine governing system considering a super long headrace tunnel is established and the dynamic sliding mode controller is designed. Then, the controller parameters are optimized by a hybrid optimization algorithm of particle swarm optimization and gray wolf optimization（PSOGWO）. Finally, the dynamic sliding mode controller is adopted for trajectory tracking experiments of hydraulic turbine governing system with sinusoidal and step signals which are used to evaluate the superiority and effectiveness of different controllers. The simulation results indicate that the designed dynamic sliding mode controller not only improves the control performance of the hydraulic turbine governing system and the convergence time of trajectory tracking, but also can significantly reduce the chattering effect of sliding mode control and the error of trajectory tracking.