In order to solve the problem of how to choose the installation position of Distributed Power Flow Controller (DPFC), the equivalent model of DPFC is established after analyzing the running principle of distributed power flow controller. Then, the optimal allocation model of DPFC is based on the equilibrium of power flow distribution of transmission section and the life cycle return rate of DPFC. Using the improved particle swarm optimization algorithm to solve the proposed model, the DPFC can be installed on best lines and the increase of the rate of transmission section of the trend can be gotten. The simulation results of the IEEE39 nodes system and the provincial 500 kV system show that the DPFC device can reallocate the power flow on the cross-section connection line, and verify the rationality of the equivalent model and the optimal configuration model and the effectiveness of the improved particle swarm algorithm. This work is supported by Science and Technology Project Headquarters of State Grid Corporation of China (No. 52150016000Y).