If the trip of an overload line causes cascading trip in the corresponding transmission section， emergency overload control should be executed to ensure the security of the transmission section. The primal-dual interior point method is used to achieve the control scheme for eliminating line overload by solving non-linear programming problem. The equal and opposite adjustment in pairs is introduced to avoid the out-of-limit of the balancing machines. In order to minimise adjustment and avoid load shedding under serious conditions， the integrative sensitivity is calculated according to the combined influence on the overload lines and close-to-limit lines， and the control nodes are separated into positive and negative output nodes. For possibly avoiding new overloads and reducing corrective times， the range of key transmission lines is expanded from including soly the close-to-limit lines to the transmission section that including the overload line. The efficiency and validity of the algorithm is verified by the calculation results of CEPRI 36-node test system.