To　increase　the　span　capacity　of　arch　bridges,　combined　with　structure　and　construction　characteristics　of　stiff-skeleton　reinforced　concrete　arch　bridge,　the　structure　of　steel　brace-steel　reinforced　concrete　(SRC)　chord　composite　truss　arch　was　proposed,　using　steel　braces　instead　of　concrete　webs,　so　it　was　helpful　to　save　the　pouring　of　concrete　webs　and　reduce　self-weight　with　this　new　composite　truss　rib,　to　meet　the　goals　of　enlarging　the　arch　bridge　span.　To　investigate　the　mechanical　characteristics　of　this　kind　of　connections　of　composite　arch,　test　on　3　composite　connections　and　1　concrete　filled　steel　tube　(CFST)　connection　were　carried　out　and　the　failure　mechanic　of　connections　was　also　analyzed　and　discussed,　taking　thickness　of　chord　outsourcing　concrete　as　main　parameters　on　the　basis　of　design　research　of　steel　brace-SRC　chord　composite　truss　arch　bridge.　The　results　show　that　all　composite　connection　specimens　are　failed　firstly　by　cracks　of　chord　outsourcing　concrete,　and　the　failure　of　concrete-filled　steel　tube　connections　occurred　finally.　Outsourcing　concrete　has　little　effect　on　the　force　of　tensile　brace　and　compressive　brace.　Stiffness　of　composite　tensile　connections　is　larger　than　that　of　CFST　tensile　connections.　Crack　load　of　outsourcing　concrete,　the　thicker　of　the　outsourcing　concrete,　the　larger　of　crack　load　are　affected　by　thickness　of　chord　outsourcing　concrete,　but　thickness　of　chord　outsourcing　concrete　has　little　effect　on　the　ultimate　bearing　capacity　of　composite　connections.　The　outsourcing　concrete　coefficient　of　composite　connection　is　advised　as　0.50　or　so.　The　ultimate　bearing　capacity　of　tensile　connection　can　be　calculated　in　light　of　punch　failure　mode,　and　compressive　connection　can　be　calculated　by　effective　width　failure　mode,　but　the　calculation　results　of　connections　are　conservative.　The　research　achievements　can　be　references　for　the　design　of　steel　brace-SRC　chord　composite　truss　arch　bridge,　and　the　design　of　such　similar　connections.　©　2017,　Editorial　Department　of　China　Journal　of　Highway　and　Transport.　All　right　reserved.