Recently, the East Asia region's air transport system faces dynamic movements such as, economicand air traffic growth, emerging LCC, new hub airports and so on. The prospect of future air demand distribution is an important task for air transport policy planning. This article proposes a network model for the analysis of East Asia's international air passenger flow pattern based on user equilibrium problem. Applying the model to some future scenarios; growth of China's air demand, downsizing and Kansai Airport's network development, the author estimates the influence on passenger flow.