To solve the maximum power tracking problem of a direct-drive permanent magnet synchronous wind power generation system, an adaptive backstepping integral sliding mode control with command-filter is designed. The non-linear model of the system is established. The controller is designed based on the back-stepping method and the second-order sliding mode differentiator is introduced as a command-filter to avoid the problem of differential expansion and controller saturation in the traditional back-stepping control. The compensation signal is designed for the filtering error. Considering the changes of system parameters and the influence of unmodeled parts of the system during operation, a projection adaptive algorithm is introduced to improve the dynamic performance of the system and ensure that the adaptive estimation is bounded. In order to improve the robustness of the system, integral sliding mode control is introduced. Finally, the stability of the system is proved by the Lyapunov method. The simulation results verify the validity of the designed controller. Compared with traditional PI control and command-filtered backstepping controller, the designed controller has faster response speed and better robustness. This work is supported by Natural Science Foundation of Jiangsu Province (No. BK20181021) and Open Fund of Jiangsu Collaborative Innovation Center for Smart Distribution Network (No. XTCX201902).