A network reconfiguration method applicable for transmission network fault emergency treatment is proposed. This method establishes a mathematical model of transmission network emergency reconfiguration based on MIQP (Mixed Integer Quadratic Programming). In order to improve the solution efficiency, the sensitivity analysis method is first applied to select the reconstructed branch set, which can reduce the calculation scale. Then, the quadratic $AC$ power flow constraint is established based on the rectangular coordinate system, and the linear mode of the short-circuit current constraint is established, and the solution scale of the short-circuit current constraint is reduced by the WARD equivalent method. The primal-dual interior point method and branch and bound method are used to solve the model. The simulation program is compiled by C++. The validity and correctness of the proposed model are verified by applying a provincial transmission network model.