A　one　dimensional　steel-concrete　composite　beam　element　model　was　established　by　adopting　finite　element　method,　and　the　element　stiffness　matrix　was　derived　by　using　the　direct　stiffness　method　and　taking　into　account　the　effect　of　interface　slip.　The　interface　slip　and　deflection　of　simply　supported　composite　beams　were　calculated　by　using　finite　element　program,　and　the　results　were　compared　with　those　of　closed　solutions.　The　comparison　shows　a　good　agreement,　and　at　the　same　time　it　can　be　found　that　the　impact　of　interface　slip　on　deflection　of　composite　beams　is　significant.　In　order　to　decrease　interface　slip　effectively,　an　optimal　arrangement　method　was　proposed　uniformly　distributed　shear　connectors,　which　was　stepwise　uniform　distribution　for　shear　connectors　without　increasing　the　number　of　shear　connector.　After　comparing　the　distribution　ratio　of　shear　connectors　between　the　region　near　to　the　beam　end　and　the　region　near　to　the　mid-span,　namely　5:5,　6:4,　7:3,　and　8:2,　the　distribution　ratio　7:3　is　an　optimal　distribution.　And　this　distribution　method　can　effectively　decrease　interface　slip　and　deflection　of　composite　beams　and　increase　composite　effect.