Urban　public　transport　is　a　very　essential　mode　for　urban　residents＇　commute　travel;　however,　the　unbalanced　spatial　and　temporal　distribution　of　travel　demand　usually　leads　to　passenger　flow　congestion　risk　at　certain　section　and　time.　Meanwhile,　the　risk　is　short　of　quantified　description.　Based　on　the　Pressure-State-Response　framework,　the　study　puts　forward　three　bus　passenger　flow　congestion　risk　evaluation　indexes　including　the　alternative　pressure,　the　congestion　intensity,　and　the　transport　efficiency.　Then,　the　evaluation　model　is　proposed　based　on　the　entropy　method,　and　the　risk　is　divided　into　four　levels　by　K-means　clustering.　The　article　considers　the　3rd　Ring　Road　corridor　in　Beijing　as　a　case　to　identify　the　risk　level.　The　results　show　that　the　risk　in　the　peak　hours　of　weekdays　is　generally　about　1.5　times　higher　than　the　risk　in　the　weekends.　The　congestion　risk　is　stable　in　level　3　during　the　majority　time　of　morning　peak　hours.　The　duration　intensity　of　level　4　risk　is　less　than　0.1　during　weekdays,　indicating　that　the　highest　flow　congestion　can　be　quickly　evacuated　in　a　short　time.　The　integrated　passenger　risk　identification　and　evaluation　model　was　proposed　to　identify　the　passenger　flow　risk　level　and　induce　the　network　flow　distribution　more　reasonable.　The　study　also　provides　technical　support　for　ensuring　the　public　transit　system　safety.