When　the　plastic　hinge　method　is　used　to　simulate　the　elasto-plastic　properties　of　concrete-filled　steel　tubular　structures,　the　plastic　interactive　yield　surfaces　of　concrete-filled　steel　tubular　column　sections　need　to　be　defined.　Although　the　fiber　model　approach　can　be　well　applied　to　the　yield　surface　analysis,　the　numerical　method　is　still　complicated　for　the　real　applications.　Therefore　based　on　the　experimental　and　theoretical　researches　on　concrete-filled　square　steel　tubular　(CFST)　members,　this　paper　develops　one　method　to　determine　the　elastic　element　parameters.　Then　a　simplified　approach　to　quickly　define　the　axial　force-moment　interactive　plastic　yield　surface　of　concrete-filled　square　steel　tubular　columns　is　developed　through　theoretical　analysis　and　a　large　number　of　parametric　analyses.　Finally,　the　fiber　model　method　is　adopted　to　verify　the　feasibility　and　validity　of　the　proposed　method.　Results　of　the　two　methods　are　in　good　agreement,　which　indicates　that　the　proposed　method　is　reliable.