A new optimal decoupling control method is proposed for linear multi-variable systems, by combining feedforward decoupling control with finite-time optimal tracking control. Firstly, the differential equation on outputs is derived, and then the internal matrix and control input matrix are respectively decomposed into a diagonal matrix and the one whose diagonal elements are zeros. Then, an intermediate virtual variable is introduced, and the feedforward and output feedback methods are used to decouple the system. Finally, the finite-time optimal tracking control method is adopted to realize the tracking of the outputs of the closed-loop system to arbitrary reference inputs. Simulation results show the effectiveness and superiority of the proposed method.