Generation schedule security correction is an important part of power system operations planning and system operations. A new strategy for security correction of generation schedules is proposed. The minimum bias based security constrained economic dispatch（SCED） model is used in this strategy. Furthermore， by relaxing unit power generation limit constraints， if the system security cannot be achieved by merely adjusting generation outputs， then the overload of flow gate can be alleviated by adjusting the unit commitment states. Consequently， the robustness of security correction can be increased. Analysis of actual system examples shows the effectiveness of the proposed algorithm. On this basis， linear programming-based scheduling system has been developed and applied to a provincial power grid successfully.