Abstract: To fully understand the operations of a subsea gas pipeline and ensure the safety of the pipeline, simulation model and corrosion prediction model are established to analyze different typical operating conditions under water dew point and saturation moisture contents. Distribution of flow parameters, flow pattern, effusion, hydrate formation and corrosion of the pipeline are acquired. Results show that no hydrate is formed and the operating parameters of the pipeline are within the scope of design under both moisture contents. In particular, under water dew point moisture content, the effusion is near zero, the flow pattern in pipe is single-phase flow and there exists only a slight corrosion at the riser. Under saturation moisture content, the effusion is greater, the flow pattern in pipe is stratified flow and there exists moderate corrosion in entire pipeline. The results can provide a reference to the effectively protecting the subsea gas pipeline.