With the rapid development of air transport industry, how to use limited airport facility resources is the main problem to be solved. As the core of transportation resources, it is very important to allocate and use the gates efficiently and reasonably. Based on the theory of network flow, this paper establishes a multi-objective optimization model to balance the multi-party interests of passengers, airlines and airports, and solves it by using ILOG CPLEX optimizer. It uses the weighting method of linear to assign multi-objective weights, so as to obtain the optimal allocation scheme with the maximum overall efficiency. Taking an international airport as an example, the results show that the average solution speed of multi-commodity network flow modeling method is 38.31% higher than that of traditional modeling method in large-scale gate assignment problem; Compared with the greedy heuristic, the optimal allocation scheme reduces the walking distance of passengers by 2.08%, the waste rate of gate by 4.69%, and the cost of airlines. By analyzing the results of gate assignment under different weights, it can provide theoretical guidance for the actual operation of the airport.