Abstract: To describe the real dynamic process of inter airport delay propagation and understand the mechanism of delay propagation, a delay propagation relation network based on transfer entropy is established and analyzed with cases in this paper. The delay time series of each airport was obtained by flight data processing. The transfer entropy causal analysis method was used to construct the delay propagation network among all airports. The complex network theory was used to analyze the network. The results of the case study show that in the daily communication interaction of delay, small airports, especially 4C airports, are always transmitting delay to the outside. For airlines, the systems of smaller airlines are more prone to occur delay propagation. These results provide theoretical support for the formulation of delay propagation mitigation measures.