Abstract: To clarify the influencing factors and formation mechanism of departing passenger aggregation in a terminal and improve the operational safety and efficiency of the terminal,this paper improves the DEMATEL-AISM by applying partial order set theory to overcome empirical and uncertain threshold determination in the traditional joint modeling.The importance ranking and correlation of the influencing factors are investigated by combining causality-centrality,factor weighting diagrams and antagonistic hierarchical topology diagrams to conduct an in-depth analysis of the causes of passenger aggregation in the terminal.The practicality of the method is also verified by using a major airport in southwest China as an example.The research results show that flight schedule change,extreme weather and peak passenger flow are at the top of the antagonistic hierarchical topology diagram,and the corresponding weights based on the sum of the absolute values of the centrality-causality are 0.16,0.11 and 0.08 respectively,which are the most direct factors influencing the departing passenger aggregation in the terminal.Besides,terminal power supply facilities,passenger flow and aircraft mechanical failures at the bottom of the model are the most fundamental factors.The study shows that it is necessary to improve service awareness and guarantee capabilities of the airport and related entities to cope with large-scale terminal passenger gatherings.