The　vehicle　flow　under　a　protected　left-turn　phase　is　commonly　affected　by　pedestrians.　This　paper　investigates　the　average　operating　speed　at　the　saturation　flow　rate　with　and　without　pedestrian　traffic,　and　evaluates　the　effect　of　pedestrians,　using　the　method　of　significant　analysis.　The　influence　factors　contain　the　position　(inside　or　outside　of　left-turn　vehicle＇s　trajectory)　and　the　number　of　pedestrian　and　the　distance　between　the　vehicle　and　pedestrians.　The　degree　of　pedestrian-vehicle　impact　is　defined　in　four　levels　and　the　speed　profile　for　the　queuing　vehicles　in　different　impact　levels　is　fitted　by　curve　fitting　software.　The　results　show　that　saturation　flow　speed　is　mainly　affected　by　the　position　of　pedestrian　(inside　or　outside　of　left-turn　vehicle＇s　trajectory),　and　the　distance,　while　the　number　of　pedestrians　is　not　an　influence　factor.　The　effect　on　the　left-turn　saturation　flow　by　both　sides　of　pedestrians　is　same　to　the　effect　by　pedestrians　on　one　serious　side.　The　speed-time　profile　indicates　an　＇S＇　shape　from　queuing　vehicles　start　to　reach　the　stable　saturation　flow,　the　vehicles　need　more　time　to　reach　the　saturation　flow　when　affected　by　the　pedestrians,　and　the　saturation　speed　is　lower.　However,　the　＇S＇　shape　of　the　speed-time　profile　is　not　affected.　These　findings　may　help　lay　a　foundation　for　a　better　traffic　management.　Copyright　©　2015　by　Science　Press.