Abstract: In order to determine the reasonable volume of the slug catcher at the terminal of submarine wet gas pipeline, the submarine pipeline and the slug catcher were taken as one complete unit and the steady-state simulation software Pipeflo was used to simulate and calculate the wet gas pipeline. Firstly, the liquid flow rate of slug catcher was determined according to the results of steady-state simulation. Secondly, the slug volume during pigging operation was determined, and the storage volume of slug catcher and the buffer volume of water were defined preliminarily. And finally, the slug volume during Ramp-up operation was calculated as per the liquid volume detained in the pipeline for different flow rates, the drainage capacity and volume of slug catcher were checked, and the volume of slug catcher at the terminal of pipeline was ultimately determined. It is indicated that the maximum slug volume during pigging and Ramp-up which is determined based on the steady-state calculation results at different flow rates is relatively in line with the simulation result of software OLGA. Therefore, the volume of slug catcher determined based on steady-state simulation is reasonable and feasible. This method is simple and convenient, and provides the technical support for the early study of the project.