With the growing multiple types of electricity load and greater integration of new energy into a power grid, congestion in and urban distribution network becomes more serious. This threatens the security of the power grid and the reliability of power supply. The local congestion of the urban transmission network can be alleviated by the spatial load transfer characteristics of high voltage distribution network reconfiguration and time load transfer characteristics of charge/discharge of battery energy storage systems. Thus, a coordinated dispatch strategy considering both these strategies is proposed. First, the model of the distributed network reconfiguration and the flexible scheduling model of a battery energy storage system are introduced. Then security distance is defined as the security index, which combines the available transmission capacity and topology to assess the effect of the proposed coordinated dispatch strategy comprehensively. Finally, a local high voltage distribution network of a city is used to verify the effectiveness of the proposed coordinated dispatch strategy. The simulation results show that the proposed method can improve the distribution of source and load over a large temporal-time scale. It is an effective way of alleviating congestion and promoting the security margin of a 220 kV transmission network. This work is supported by the National Natural Science Foundation of China (No. 51977133) and the Science and Technology Project of State Grid Sichuan Electric Power Company (No. 52199718001J).