The grid branch-node coefficient matrix is obtained first based on the gird parameters and wide area information. Using this matrix， the generators and load shedding nodes can be sorted accordingly. Secondly， the sum of generators' positive outputs， negative outputs and load shedding are optimized using particle swarm optimization（PSO）. Thirdly， the sum of positive output， negative output and load shedding are rationally distributed by assorting generators and load shedding nodes， and the corresponding flow transferring control strategy is formed aiming at accurately controlling of flow transfers in the system. This method can precisely adjust and control line overloads due to re-sectioning of single branch or multiple branches in a simple and rapid way. The simulation of New England 39-bus system demonstrates that the control strategy is effective and fast， and that the method has good practical prospect.