Multimodal　public　transport　network　(MPTN)　plays　an　important　role　in　relieving　road　traffic　pressure　for　metropolitan　area.　Nevertheless,　the　impact　of　an　accident　happened　in　an　individual　station　may　not　only　disrupt　the　station　itself　or　the　single　lines　that　go　through　the　station　but　also　spread　over　the　whole　network.　Therefore,　identifying　the　vulnerable　stations　is　essential　for　improving　the　MPTN　management　against　the　systematic　risk　caused　by　accidents.　In　this　paper,　we　proposed　a　route　diversity-based　approach　to　measure　the　vulnerability　of　stations　in　MPTN　based　on　the　complex　network　theory.　The　route　constraint　parameters　were　established　to　reflect　the　travel　time　restriction　in　constructing　the　set　of　passengers＇　acceptable　routes.　In　addition,　an　algorithm　was　formulated　to　rapidly　calculate　the　route　diversity　index　and　meanwhile　avoid　the　＂overlapping　routes＂　problem.　A　simple　virtual　network　was　used　as　a　numerical　example　to　compare　the　proposed　approach　with　the　vulnerability　evaluation　approaches　based　on　degree　centrality　and　betweenness　centrality.　Finally,　the　proposed　approach　was　applied　to　the　MPTN　of　Beijing　to　explain　its　effectiveness　and　potential　applications.　The　results　show　that　the　proposed　method　can　efficaciously　estimate　vulnerable　nodes　compared　with　degree　centrality　and　betweenness　centrality.　Meanwhile,　the　acceptable　routes　between　any　OD　pairs　in　the　MPTN　are　1-10　according　to　the　constrained　parameter.　In　addition,　the　average　number　of　acceptable　routes　between　OD　pairs　of　Beijing　MPTN　is　3.649.　By　ranking　the　stations　according　to　their　vulnerability,　it　can　be　found　that　the　top　5　vulnerable　stations　are　all　external　traffic　hubs　or　the　stations　around　famous　commercial　areas.　The　results　suggest　that　these　stations　are　significant　for　external　transport　as　well　as　crucial　for　internal　urban　transportation　systems.　The　research　output　could　contribute　to　the　MPTN　management　in　accident　prevention　and　emergency　handling.