In order to improve the efficiency of flight ground support, an AOE network was constructed according to the flight ground guarantee process of an airport, and the "critical path" of flight ground support operation of the airport was calculated through the flight node data recorded by the airport A-CDM system. By analyzing the compressible process on the critical path, the ground guarantee operation flow of the airport is optimized. Based on the actual data of flight ground guarantee at an airport in southwest China, the abnormal data caused by force majeure were eliminated, and the flight transit time before and after the optimization of the guarantee process was calculated. The comparative analysis shows that, among the 33 sets of flight data, the optimized support operation process using AOE network reduces the ground guarantee operation time by 6.1min/ flight on average, which effectively improves the operation efficiency of the airport.