In order to make the control of interconnected grid frequency have better load adaptability and maintain the economic stability and reliable operation of the grid, a design method of multivariable predictive controller and its algorithm are proposed. They are based on the state-space model of the interconnected grid while considering the regional capacity constraint. To solve the problem with the control relying on
(the frequency error coefficient) in most such questions, the quadratic programming (QP) solving is employed. And so the optimal control is ensured even when there is interconnected grid support. According to the modeling and simulating of the two-area grid frequency control system, the proposed predictive algorithm is compared with the conventional algorithm via PI regulator in single area and dual zone load step disturbance, random white noise disturbance and model mismatch, etc. The results indicate that the proposed predictive control algorithm can significantly improve the recovery performance of the grid system frequency.