Abstract: Condensate gas has special behaviors, which will lead to a slug flow formed in the gathering process and seriously affect the stability and safety of gathering system, therefore, it is vital to successfully predict the slug flows so as to ensure the normal running of condensate gas gathering pipeline. Taking the gathering pipeline of Baka Condensate Gasfield as an example, the paper analyzes the possibility of formation of slug flow in the pipeline according to the gas phase equilibrium diagram of gas component with Hysys firstly, and then analyzes the operation states of the pipeline under different pressure, temperature and elevation, and finally determines the formation of slug flow in the pipeline according to the liquid volume fraction and the pipeline liquid holdup volume in the pipeline. Results show that with the pressure's increase, the media in the pipeline are changed from two-phase flow into single-phase flow (gas phase), then converted to two-phase flow again, and finally to a slug flow. This paper provides some practical measures to the prevention of slug flow formation based on the simulation analysis results.