Driving　speeds　are　higher　on　freeways,　and　the　visibility　reduction　occurring　in　freeway　fog　zones　often　increases　traffic　accidents.　This　study　aims　at　assessing　the　impact　of　different　levels　of　connected　vehicle　fog　warning　systems　on　driving　behavior　and　safety.　A　connected　vehicle　fog　warning　system　is　developed　based　on　driving　simulators,　and　virtual　scenes　are　developed　based　on　fog　zones.　The　connected　vehicle　technology　includes　three　levels:　a　normal　level,　a　level　including　a　human-machine　interface,　and　a　level　with　both　a　human-machine　interface　and　dynamic　message　signs.　Speed　and　lateral　deviation　are　chosen　as　assessment　indicators　and　combined　with　sample　entropy　to　evaluate　the　impact　of　the　connected　vehicle　fog　warning　system　on　safety.　The　deceleration　ratio　of　the　warning　point　is　used　to　evaluate　the　efficiency　of　the　connected　vehicle　fog　warning　system.　Results　show　that　the　connected　vehicle　fog　warning　system　can　significantly　reduce　driving　speed,　and　that　there　are　differences　in　the　speed-reduction　effectiveness　for　different　technical　levels.　The　connected　vehicle　fog　warning　system　can　reduce　the　lateral　deviation　and　improve　the　lateral　driving　safety.　From　the　perspective　of　change　stability,　speed　safety　entropy　and　lateral　deviation　safety　entropy　are　increased,　which　indicates　that　the　connected　vehicle　fog　warning　system　will　negatively　impact　safety　because　of　the　additional　workload.　Drivers＇　responses　are　more　pronounced　in　the　human-machine　interface　group　compared　to　the　group　with　dynamic　message　signs,　where　the　drivers　maintained　a　lower　speed.　This　study　provides　a　reference　for　the　studies　on　connected　vehicle　technology　based　on　driving　simulators　and　supports　the　optimization,　design,　and　evaluation　of　connected　vehicle　fog　warning　systems.