A novel adaptive quasi-sliding mode control approach is proposed for a class of unknown MIMO nonlinear discrete-time systems with external disturbance. The nonparametric dynamic linearization technique is utilized in the controller design. By applying the high order sliding mode control strategy, the second order quasi-sliding mode control for this disturbance system is realized. Furthermore, according to the disturbance decoupling technique, a discrete extended state observer(DESO) is introduced into the controller design to compensate the couplings and unmodelled dynamics of the established data model, and then to realize the decoupling control and improve the control performance. Finally, theoretical analysis and simulation results show the feasibility and effectiveness of the proposed method.