Considering riser system in subsea pipeline, severe slug is a common and harmful flow pattern under low flow rate. A certain condensate gas pipeline from wellhead platform to central platform is selected to be studied. The slug flow characteristics and suppression effects of choking, gas lifting and multiphase pump controlling are simulated with OLGA. The impact of slug flow can be eliminated by choking and gas lifting controlling, while periodic variation characteristics of severe slugging can only be weakened by multiphase pump controlling.