Abstract: A long span suspension bridge with steel box girder is regarded as an engineering example.The deck has both expressways and sidewalks.There are many railings and protective nets on bridge deck,which induces remarkable vertical and torsional vortex induced vibration of bridge deck.By the section model wind tunnel test,the effects of maintenance car tracks,railings on the deck,flow splitter plates,attack angle and damping on the vortex-induced vibration（VIV） are investigated,the optimization measurements are presented to reduce the vortex induced vibration.The results of the wind tunnel tests show that the vortex induced vibration of this bridge can be effectively suppressed by optimizing the location of maintenance car tracks and installing flow splitter plates at wind nodes.