To　compare　with　the　fatigue　performance　of　circular　hollow　section　(CHS)　K-joint,　fatigue　test　on　full-scale　concrete-filled　steel　tubular　(CFST)　K-joint　model　was　conducted,　and　distribution　of　hot　spot　stress,　fatigue　performance　evolution　and　fatigue　failure　mode　of　CFST　K-joint　were　acquired　by　comparative　analysis.　Furthermore,　the　evaluation　method　used　on　fatigue　life　of　CFST　K-joint　was　discussed.　It　is　found　that　the　location　of　the　maximum　hot　spot　stress　of　CFST　K-joint　is　the　same　as　that　of　CHS　K-joint,　namely　the　crown　point　of　chord　and　tensile　brace　intersection　welding　seam　near　chord　intersecting　line,　but　the　stress　concentration　factor　of　CFST　K-joint　decreases　to　about　58%　of　that　of　CHS　K-joint,　and　its　extrapolation　method　tends　to　change　in　a　parabolic　form.　Although　fatigue　performance　evolution　of　both　of　them　can　be　divided　into　three　stages　including　initiation,　extension　and　failure　of　fatigue　crack,　the　main　extension　direction　of　CFST　K-joint　fatigue　crack　is　along　the　chord　thickness　and　the　length　of　the　welds　in　the　latter　two　stages,　respectively,　which　distinguishes　from　that　of　CHS　K-joint.　Meanwhile,　both　of　them　have　the　same　fatigue　crack　type,　namely　opening　Class　I　crack,　and　the　fatigue　fracture　of　CFST　K-joint　along　the　chord　thickness　acts　as　＇teeth＇,　whch　makes　the　extension　path　longer　than　that　of　CHS　K-joint.　Radial　stiffness　of　the　chord　of　CFST　K-joint　is　improved　by　combined　action　of　concrete　filled　in　the　chord,　which　makes　concave　and　convex　deformation　along　the　diameter　of　the　chord　much　less　than　that　of　CHS　K-joint　under　axial　loads,　and　it　is　the　main　reason　why　the　fatigue　performance　of　CFST　K-joint　is　superior　to　CHS　K-joint.　S-N　curve　for　fatigue　design　of　CFST　K-joint　established　by　the　one-point　method　has　a　higher　accuracy.　©　2020,　Editorial　Office　of　Journal　of　Building　Structures.　All　right　reserved.