Left-turn　waiting　areas　can　increase　the　capacity　of　the　left-turn　lane　in　signalized　intersection.　Firstly,　based　on　the　investigation　data　of　the　vehicles　of　the　left-turn　with　waiting　area　in　signalized　intersection,　this　paper　analyzed　their　characteristics　of　the　acceleration,　speed,　and　distance　from　the　start　to　leave　the　intersection.　Then,　it　established　an　approach　which　can　calculate　the　capacity　of　the　left　turn　lane　with　waiting　area　based　on　the　formula　of　left-turn　lane　without　waiting　area　and　carried　out　example　verification.　The　results　show　that　the　vehicles　start　successively　after　the　left-turn　phase　turning　green,　and　its　acceleration　has　a　undulant　linear　relationship　with　time.　Also,　the　waiting　area　of　the　left-turn　lane　can　improve　the　actual　capacity　significantly,　the　signal　phase　and　the　length　of　the　waiting　area　affect　the　proportion,　and　the　waiting　area　of　the　left-turn　lane　improved　the　capacity　by　10%~20%　in　the　surveyed　signalized　intersection.　©,　2015,　Editorial　Department　of　Journal　of　Chang＇an　University　(Natural　Science　Edition).　All　right　reserved.