In order to solve the problem of flight conflict caused by the increasing air traffic flow, a key point identification method of flight conflict based on flight conflict network and TOPSIS method is proposed.Firstly,based on the ellipsoidal flight reserve,the flight conflict network is constructed by the three-dimensional velocity obstacle method,and then four evaluation indexes are selected to construct the node importance evaluation index system.Finally,the entropy weight method is used to optimize the TOPSIS method to determine the position of the key conflict aircraft.The simulation results show that the proposed method accurately identifies the key conflict points in the flight conflict network,reduces the complexity of the flight conflict network, and provides reference for air traffic control services.