Abstract: Because an airplane is needed to carry out several scheduled flight services in a day，of each service linked another，one delay will propagate to the other.This paper investigates the aircraft and crew resources for the influence of flight delay and propagation and describes the process of creating a delay tree.Triggered by beginning flight delay，it developments a delay propagation tree with initial flight as its root and statistic some metrics.It analyzes the relationship among the time of day，the duration of initial delay and the propagation in an instance.Its purpose is to help the optimization of aircraft and crew schedule，thereby reduce the flight delay.