Connected　vehicle　technology　relying　on　Human　Machine　Interface　(HMI)　achieve　a　dominant　position　in　the　overall　safety　improvement.　However,　the　impact　of　HMI　on　the　driver＇s　visual　attention　cannot　be　ignored,　especially　on　the　accident-prone　foggy　freeway.　The　objective　of　this　paper　is　to　evaluate　the　level　of　distraction　caused　by　HMI　in　data　analysis　of　drivers＇　visual　characteristics　and　to　establish　a　generic　evaluation　methodology.　A　connected　vehicle　test　platform　has　been　established　based　on　the　driving　simulator,　in　which　visibility　was　set　to　the　level　of　heavy　fog　and　the　technical　condition　was　set　in　two　conditions　(with　or　without　HMI).　Measurement　of　driving　behavior　parameters　include　frequency　of　fixations　and　saccades　and　the　proportion　of　fixation.　The　researchers　compared　and　analyzed　the　driver＇s　visual　characteristics　and　the　degree　of　distraction　in　a　combination　of　indices　based　on　the　AttenD　algorithm,　setting　two　technical　conditions　in　a　heavy　fog.　Drivers　suffering　more　visual　distraction　and　interference　with　HMI　may　have　an　impact　on　the　driver＇s　driving　safety.　The　results　provide　a　generic　approach　to　evaluate　the　HMI　of　a　connected　vehicle　system　and　a　safety　assessment　methodology　for　the　connected　vehicle　system.