The　size　effect　on　the　seismic　performance　of　conventional　reinforced　concrete　columns　has　been　observed　in　terms　of　flexural　failure　and　shear　failure.　Under　earthquake　loading,　slender　columns　experience　flexural　failure,　and　short　columns　experience　flexure-shear　failure　and　shear　failure.　However,　the　effect　of　section　size　on　the　seismic　performance　of　high-strength　reinforced　concrete　columns　under　the　conditions　of　different　shear　span-to-depth　ratios　requires　further　confirmation.　For　this　purpose,　six　high-strength　reinforced　concrete　columns　with　shear　span-to-depth　ratios　of　2　and　4　were　subjected　to　cyclic　loading　in　this　study.　The　experimental　results　indicated　that　relative　nominal　flexural　strength,　energy　dissipation　coefficient,　factor　of　safety,　and　local　factor　of　safety　all　exhibited　a　strong　size　effect　by　decreasing　with　increasing　column　size.　Furthermore,　the　size　effect　became　stronger　as　the　shear　span-to-depth　ratio　was　increased,　except　for　average　energy　dissipation　coefficient.　The　observed　changes　in　the　factor　of　safety　were　in　good　agreement　with　the　Type　2　size　effect　model　proposed　by　Baant.　Thus,　based　on　the　local　factor　of　safety　and　Baant＇s　Type　2　model,　the　code　equation　for　moment　capacity　of　different　shear　span-to-depth　ratios　was　modified　to　provide　a　consistent　factor　of　safety　regardless　of　column　size.