The　deck-extension　bridges　is　the　most　widely　used　jointless　bridges　in　China　due　to　the　simple　structure　and　convenient　construction.　The　mechanical　performance　of　skewed　bridges　is　more　complex　than　that　of　right　bridges.　To　understand　the　difference　between　the　skewed　deck-extension　bridge　(SDEB)　and　the　skewed　jointed　bridge　(SJB),　a　SDEB　built　in　China　was　chosen　as　a　case　study.　The　girders　and　approach　slabs　longitudinal　displacements　were　monitored.　A　finite　element　model　(FEM)　was　implemented　by　using　the　MIDAS-Civil　software,　of　which　the　accuracy　was　verified　by　monitoring　results.　The　mechanical　performance　of　the　SDEB　and　SJB　under　different　load　cases　was　compared.　The　influence　of　different　skew　angles　on　the　mechanical　performance　of　the　SDEB　was　studied.　The　results　indicated　that　the　mid-span　bending　moment　of　the　SDEB　was　slightly　smaller　by　5%　than　that　of　the　SJB.　Compared　with　the　SJB,　the　mid-span　torque　of　the　girder　in　the　side　span　and　axial　force　at　the　girder　end　in　the　SDEB　were　significantly　larger,　which　should　be　paid　special　attentions　to　during　the　design.　The　in-plane　rotation　of　the　girder　in　the　SDEB　was　limited　by　the　approach　slab;　therefore,　the　lateral　displacement　of　the　SDEB　was　significantly　smaller　than　that　of　the　SJB,　especially　for　the　skew　angle　of　30°.　Bearing　unseating　and　deck　cracks　may　be　improved　in　SDEB.　©　IABSE　Congress　Nanjing　2022　-　Bridges　and　Structures:　Connection,　Integration　and　Harmonisation,　Report.　All　rights　reserved.