Abstract: Due to the special characteristics of concerning in probability safety analysis(PSA) in the new reactor design phase, such as insufficient information, unavoidable iterations, complicated communications among multiple specialties and so on, efficient measures were developed to further the projects. A time-related event tree approach presented in the paper is one of them. Compared with ordinary event tree, the time-related event tree intends to illustrate not only the accident propagation processes, but also the key time points when safety systems, signals and operator actions are challenged and the durations. It seems to be a good bridge between designers and PSA engineers for the consistent understanding and more efficient information exchanging.