Stress-strain　relationships　of　concrete　circular　columns　confined　by　interlaminated　hybrid　fiber　sheets　of　carbon　fiber,　aramid　fiber,　glass　fiber,　and　basalt　fiber　are　experimentally　researched　in　this　paper.　Results　show　that　HFRP　can　evidently　increase　the　strength　of　circular　columns,　and　significantly　improve　the　ductility.　Based　on　the　experimental　data　and　analysis　on　the　research　production,　a　constitutive　confinement　model　is　developed　for　concrete　circular　columns　confined　with　HFRP.　The　feature　of　the　model　includes　the　effects　of　HFRP　confinement　on　the　concrete　microstructure　by　evaluating　the　internal　concrete　damage　using　the　axial,　lateral,　and　volumetric　strains,　which　introduces　that　the　confinement　model　is　simple　and　has　a　physical　and　fundamental　interpretation　with　the　mechanical　behavior　of　concrete.　Meantime,　the　secant　concrete　modulus　is　used　in　the　model　and　expressed　as　a　function　of　the　secant　modulus　softening　coefficient.　The　HFRP-confined　concrete　model　accurately　predicts　the　stress-strain　relationship　of　concrete　circular　columns　confined　with　HFRP　as　verified　in　comparison　with　experiments.