A new generalized predictive control algorithm of MIMO systems based on grey model is presented in this paper. It establishes a grey model instead of CARIMA model, and eliminates the coupling of MIMO system by using feed-forward decoupling. It has the feature of identifying small parameters, and avoiding online solving the Diophantine equation and inverse matrix. So the computation load of algorithm can be reduced greatly, and real-time property is advanced. The simulation results show that the proposed algorithm is fast, efficient and feasible