GPC (Generalized Predictive Control) is widely used in the control of plant with inertia and delay. This paper proposes feed-forward and feedback GPC in the control of MIMO system. The coupling is treated as knowable exterior disturbance and considered during the designing process of GPC controllers. With structure analysis, the new controller is equivalent to feed-forward and feedback control system. But the new GPC controller has the merits of rolling optimization and without tuning parameters. The new method is introduced into the control of 300MW unit load system which is a 2.. 2 multivariable system. Simulations prove that the new method could meet the requirements of quick load response ability and maintaining the stability of steam pressure. The robustness of the new method is also satisfactory.