The　integral　abutment　bridges　(lABs)　concept　has　received　considerable　interest　among　bridge　engineers　owing　to　their　enormous　benefits　due　to　elimination　of　expensive　joints　and　reduced　installation　and　maintenance　costs.　However,　a　standard　design　method　for　lABs　does　not　exist.　Several　factors　must　still　be　investigated　and　analysed　to　gain　a　better　understanding　of　the　behavior　of　lABs.　As　for　lABs,　approach　slabs　not　only　provide　vehicles　with　a　smoother　transition　from　pavement　to　bridge　but　also　move　the　end　expansion　joint.　Because　approach　slabs　being　often　rigidly　connected　with　abutment　and　girders,　they　will　be　loaded　and　move　as　a　integer.　This　paper　takes　Shangban　Bridge　in　Fujian　province　of　China　-The　longest　IAB　in　China　as　engineering　background　and　develops　two　different　space　finite　element　models　without　and　with　approach　slabs.　Effects　of　approach　slabs　on　the　behavior,　deformation　and　expansion　or　contraction　of　girders,　the　behavior　of　abutment　pile　foundation　and　the　dynamical　characteristics　of　bridge　under　temperature　change　were　analysed.　The　results　from　the　study　should　aid　in　the　design　and　practice　of　lABs.