In order to optimize the flight schedule of an airport cluster and improve its operational efficiency，the characteristics of corridor gates and flight flows were considered in order to determine the priority of corridor gates. A model was constructed to minimise the total cost of schedule adjustments by adjusting flight departure times during the strategic phase. An improved genetic algorithm was adopted to solve the model. The Beijing-Tianjin-Hebei airport cluster was used as a case study for the simulation analysis. The results show that corridor gate scheduling is significantly influenced by its own characteristics. While the amount of schedule adjustment considering flight flow characteristics increases by 2.43% compared to a scenario without such consideration，the overall adjustment cost decreases by 6.91%. Additionally，the number of flights during peak hours is significantly reduced，effectively alleviating the problem of flight delays caused by corridor gate capacity being exceeded. It can therefore be concluded that the proposed model effectively optimises flight schedules while reducing delays and operational costs.