Abstract: In response to airport gate assignment problem in considering irregular operations of airport and flights, a mixed integer programming model is built. Aircraft waiting time is introduced in order to adapt to the actual operation condition. By using ILOG CPLEX optimizing software, flight delay and gate fault situation are simulated as an example. A solution is found in 5 seconds with 2.1 GHz CPU, RAM, 2.0 GHz configuration. From the gate assignment plan, compared with regular operation, the total passenger walking distance is increased by 130 meters only when a gate fault occurs, and it remains unchanged when flights are delayed. With the effectiveness in solving the airport gate assignment problem in irregular situation, the model is significant in practical applications.