In practice, most systems are nonlinear and multivariable in character, which makes their control theories find immediate and increasing attention. Various control strategies in recent years have been proposed for these systems, such as robust control, backstepping control and sliding mode control. Compared with the single input and single output systems, the control design for MIMO nonlinear systems becomes much more complex and difficult since the couplings and uncertainties in systems. It is therefore essential to develop an appropriate control strategy for these MIMO nonlinear systems from both practical demand and theoretical challenge. Generally, almost all practical systems are facing various constraints, which can be classified into two categories, performance-related constraints (e.g., transient and steady state performance) and capability-related ones (e.g., input saturation).