Introduction:　The　optimization　of　public　transport　(PT)　systems　to　ameliorate　urban　traffic　problems　and　living　environment　requires　a　deep　understanding　of　PT　usage　behaviour.　However,　there　is　a　lack　of　scientific　measurement　of　the　influence　on　passengers＇　PT　dependence　(PTD)　during　emergent　public　health　events.　Methods:　An　extended　theory　of　planned　behaviour　and　an　online　survey　scheme　are　proposed　to　investigate　the　influence　of　psychological　and　objective　factors　on　passengers＇　PTD　under　an　emergent　public　health　event　in　Beijing,　China.　Then,　four　structural　equation　models　are　estimated　to　analyse　the　PTD　influence　mechanism　of　different　groups　of　passengers.　Results:　The　objective　condition　factors　exert　indirect　effects　on　passengers＇　PTD　via　the　psychological　factors.　Individual　attributes　have　small　influences　on　passengers＇　PTD,　while　the　environment　has　a　significant　positive　effect.　Subjective　norms　have　the　highest　influencing　effect　on　passengers＇　PTD,　and　passengers　with　a　relatively　high　PTD　level　have　the　risk　of　shifting　to　other　transportation　modes　under　the　emergent　public　health　events.　Conclusions:　The　influence　mechanism　of　emergency　public　health　events　on　the　PT　dependence　of　different　passengers　is　heterogeneous.　The　targeted　policies　should　be　implemented　for　different　passengers　to　improve　the　PT　market　share　and　residents＇　health　under　emergent　public　health　events.