In　order　to　investigate　the　effect　of　constitutive　behaviors　on　mechanical　performance　of　members　and　structures,　the　constitutive　relationship　tests　of　LYP100　low　yield　point　steel　were　carried　out　firstly.　The　monotonic　behavior,　ductility,　hysteretic　behavior,　energy-dissipation　capacity　and　cyclic　constitutive　model　were　analyzed.　Based　on　these　results,　the　constitutive　relationship　of　low　yield　point　steel,　normal　strength　steel　(Q345B)　and　high　strength　steel　(Q460D)　were　fully　compared.　Finally,　the　predicted　hysteretic　behaviors　of　different　steels　with　both　cyclic　constitutive　model　and　ideal　elastic-plastic　model　were　compared　to　further　discuss　the　significant　effect　of　constitutive　relationship　on　members　and　structures.　The　results　show　that　the　monotonic　and　cyclic　tensile-to-yield　ratios　of　low　yield　point　steels　are　more　than　2.0~3.0,　2.0~3.0　times　of　normal　strength　steel　and　high　strength　steel.　Meanwhile,　low　yield　point　steels　have　better　ductility　and　energy　dissipation　capacity.　Because　low　yield　point　steels　have　obvious　isotropic　behaviors,　significant　difference　is　observed　between　the　calculated　results　using　cyclic　constitutive　model　and　ideal　elastic　plastic　model.　Therefore,　for　structural　analysis,　an　appropriate　constitutive　relationship　should　be　adopted　according　to　different　steels.　©　2017,　Engineering　Mechanics　Press.　All　right　reserved.