The　reversed　cyclic　loading　test　of　a　large-scale　beam-column　joint　is　carried　out　to　study　its　seismic　performance,　including　the　load-carrying　capacity,　failure　pattern,　hysteretic　behaviors,　ductility　and　energy　dissipation　characteristics,　and　the　results　are　compared　with　other　relatively　smaller　specimens　for　evaluation　of　the　size　effect　on　the　seismic　performance　of　structural　components.　The　test　results　show　that　the　process　of　joint　failure　starts　from　cracking,　then　yielding　developed　at　beam　end,　and　then　the　joint　becomes　fully　cracked　and　finally　leads　to　failure.　However　the　experiments　also　show　that　as　the　size　increases,　the　quantities　of　inclined　cracks　significantly　increased　and　the　growth　rate　of　diagonal　crack　to　both　ends　of　the　joint　accelerated.　Moreover,　for　larger　specimen　the　cracking　growth　tendency　of　middle-width　and　ends-narrow　in　diagonal　crack　belt　becomes　more　obvious,　and　the　shear　capacity　and　deformation　capacity　in　joint　core　is　obviously　decreased.　In　particular,　at　the　late　loading　stage,　the　stiffness　decay　for　the　large　specimen　accelerated,　energy　dissipation　and　ductility　decreased　obviously.　The　size　effect　of　structural　components　should　be　paid　more　attentions　in　seismic　design　of　RC　structures.