This　paper　proposes　a　novel　structural　design　for　stirrups-stiffened　square　concrete-filled　double　-skin　steel　tubular　stub　columns　(SCFDST)　that　offers　high　capacity　and　superior　advantages　in　terms　of　low　consumption　of　concrete　and　steel,　as　well　as　economic　efficiency.　The　study　includes　an　axial　pressure　test　on　two　sets　of　8　SCFDST　columns　with　varying　hollow　ratios　and　stirrup　ratios,　with　a　specific　focus　on　the　influence　of　stirrups　on　mechanical　properties.　Experimental　results　demonstrate　that　stirrups　significantly　enhance　the　mechanical　properties　of　SCFDST　columns　with　large　hollow　ratios,　including　stiffness,　bearing　capacity,　and　ductility,　with　a　more　pronounced　effect　observed　as　the　stirrup　ratio　increases.　A　three-dimensional　solid　finite　element　(FE)　model　of　the　SCFDST　columns　is　developed　and　validated　using　ABAQUS　software　and　appropriate　constitutive　models.　Parameter　analysis　is　then　conducted　based　on　the　FE　model,　revealing　that　the　stirrups　not　only　restrain　the　concrete　itself　but　also　provide　additional　restraint　by　limiting　the　deformation　of　the　steel　tube.　This　improvement　effect　was　more　significant　in　the　middle　of　steel　tubes　section.　When　stirrup　ratio　was　0.015,　the　steel　tube　had　the　highest　constraint　efficiency　on　the　concrete.　The　study　introduces　a　constraint　enhancement　factor　to　represent　the　enhanced　restraining　effect　of　stirrups　on　the　steel　tube,　which　is　incorporated　into　a　fresh　equation　for　determining　the　maximum　bearing　capacity　(Nu)　of　SCFDST　columns.　The　derived　formula　offers　clear　physical　meaning　and　high　accuracy,　building　upon　the　existing　formula　for　CFDST　columns.