To　explore　the　characteristics　of　mixed　traffic　flow　with　platoons　of　intelligent　connected　vehicles,　a　mathematical　analytical　expression　that　can　reflect　the　random　distribution　characteristics　of　different　types　of　vehicles　in　mixed　traffic　flow　is　proposed.　Considering　the　dynamic　characteristics　of　desired　headway　changing　with　speed,　the　car-following　model　of　different　types　of　vehicles　was　established.　Based　on　this,　the　fundamental　diagram　of　the　mixed　traffic　flow　with　intelligent　connected　vehicle　platoons　was　derived.　Moreover,　the　sensitivity　analyses　of　the　market　penetration　rate　of　connected　vehicles　and　the　maximum　platoon　size　were　made.　The　simulation　results　show　that　the　traffic　capacity　is　gradually　improved　with　the　increase　of　the　market　penetration　rate　p.　When　p0.5,　the　improvement　of　capacity　is　significant　as　the　market　share　increases.　In　addition,　with　the　increasing　popularity　of　intelligent　connected　vehicles,　the　impact　of　the　platoon　size　on　traffic　capacity　becomes　more　and　more　significant.　Meanwhile,　the　platoon　size　should　be　maintained　between　4　and　6　when　p　©　2020,　Editorial　Department　of　Journal　of　Southeast　University.　All　right　reserved.