Abstract: Adaptive back-stepping sliding mode control strategy-based controller with neural network disturbance observer (NNDO) is proposed for positioning servo system of slab thickness deviation rectification of medium density fiberboard which contains nonlinear factors, such as parameters uncertainty, interference from externality, etc. to solve rectification of slab thickness. The results show the effectiveness of NNDO-based back-stepping sliding mode control method in terms of improving position tracking and convergence rate of tracking error, reducing the chattering of control input, and improving the dynamic performance of closed-loop system and composite interference robustness. The control performance of the controller was increased.