Medium　and　small　span　bridges　make　up　a　large　proportion　of　highway　bridges　in　China.　Due　to　harsh　service　conditions，the　expansion　joints　are　prone　to　diseases，which　can　exacerbate　vehicle　vibrations，and　subsequently　lead　to　the　damage　of　the　end　bearings　and　other　components.　In　order　to　study　the　influence　of　expansion　joint　and　bearing　parameters　on　the　vehicle-induced　dynamic　response　of　simply　supported　beam　bridge，this　paper　establishes　a　numerical　analysis　method　of　vehicle-expansion　joint-bridge　coupling　dynamic　response（VBCV-J）.　The　effectiveness　of　VBCV-J　analysis　method　is　verified　using　measured　data，followed　by　an　investigation　the　influence　of　expansion　joint　and　support　parameters.　The　results　show　that：The　speed　is　closely　related　to　vehicle　vibration.　When　the　vehicle　speed　is　high　and　the　Road　Surface　Condition（RSC）is　“normal”，the　impact　effect　of　vehicles　on　expansion　joints　and　the　ends　of　beams　can　exceed　the　specified　values..　If　the　girder　in　the　expansion　joint　is　higher　than　the　pavement，the　impact　on　the　expansion　joint　will　significantly　increase，conversely，it　will　decrease.　When　the　girder　in　the　expansion　joint　is　higher　or　lower　than　the　road　surface，the　impact　at　the　end　of　the　main　beam　will　increase.　A　reduction　in　the　support　stiffness　of　the　expansion　joint　or　a　void　in　the　side　support　of　the　main　beam　will　significantly　increase　the　impact　effect　on　both　the　expansion　joint　and　the　end　of　the　main　beam.　A　decrease　in　the　stiffness　of　the　main　beam　support　primarily　results　in　an　increased　impact　on　the　entire　main　beam.　Damage　to　the　expansion　joints　not　only　affects　their　own　impact，but　also　greatly　increases　the　impact　on　the　end　members　of　the　simply　supported　beams.　During　design　and　maintenance，sufficient　attention　should　be　given　to　the　end　members　of　the　beams.　©　2024　Nanjing　University　of　Aeronautics　an　Astronautics.　All　rights　reserved.