Expressway　on-ramps　are　common　sites　of　traffic　congestion,　and　there　are　serious　confluence　conflicts.　In　a　connected　vehicle　environment,　inter-vehicle　communication　can　potentially　improve　the　efficiency　of　traffic　operations.　This　study　constructed　a　simulation　scenario　of　the　on-ramp　area　in　an　expressway.　Through　the　inter-vehicle　communication　function,　the　ramp　vehicle　can　help　reduce　the　disturbance　of　main　road　traffic　flow　caused　by　the　on-ramp　vehicle　inflow,　improving　main　road　and　on-ramp　efficiency.　The　results　show　that　(1)　when　the　traffic　flow　of　the　main　road　and　ramp　is　in　the　range　of　30–50　pcu/km/ln,　the　inter-vehicle　communication　has　a　positive　impact　on　the　traffic　operation　in　the　on-ramp　area;　and　(2)　when　the　density　of　the　main　road　and　ramp　is　40　pcu/km/ln,　the　improvement　effect　of　inter-vehicle　communication　on　traffic　efficiency　is　the　most　obvious.　Inter-vehicle　communication　can　improve　on-ramp　traffic　flow　and　provide　a　strategic　reference　for　alleviating　traffic　congestion　and　reducing　accident　risk.　©　ASCE.