Abstract: In this paper, the researchers describe a prediction model for several typical severe slug flows, establish a one-dimensional transient flow model expressed the periodic flow in mixing transport riser system that satisfied mass and momentum conservation, and compare the model calculation results with experimental data and OLGA software calculated results. Results show that the pressure trend at the bottom elbow of riser calculated by the model is in good agreement with experimental data, such as pressure trend and slugging cycle, and there is a certain difference between calculated results of the model and OLGA software, but it still falls into the acceptable range of the project. This research achievement indicates that this model can be used to perform correct numerical simulation for severe slug flow of riser system and taken as a theoretical basis for rational design of submarine riser systems.