The　aim　of　the　present　study　is　to　explore　the　influence　of　stirrup-confined　action　on　size　effect　of　high-strength　reinforced　concrete　(RC)　columns　subjected　to　small-eccentric　(e0=0.25h0)　compressive　loading.　A　series　of　eccentric　compressive　tests　of　the　mechanical　performances　of　12　geometrically　similar　high-strength　RC　columns　with　different　stirrups　ratios　(in　the　stirrup　ratios　of　0%,　0.66%)　were　conducted,　in　which　the　maximum　cross-section　size　of　the　high-strength　RC　columns　was　800　mm×800　mm.　Moreover,　a　meso-scale　simulation　method　for　the　investigation　of　the　global　mechanical　properties　of　RC　columns　was　established.　The　numerical　tests　on　the　RC　columns　with　larger　stirrup　ratios　(1.2%　and　2.4%)　was　then　carried　out　complementarily,　based　on　the　fact　that　the　present　simulation　results　were　consistent　with　the　available　test　observations.　Subsequently,　the　failure　behavior　of　the　RC　columns　under　eccentric　loadings　was　studied,　involving　the　failure　patterns,　the　nominal　compressive　stress-strain　relationships,　the　load-carrying　capacity,　the　nominal　compressive　strength　and　the　post-peak　softening　behavior.　The　size　effect　of　nominal　compressive　strength　was　also　explored.　Furthermore,　the　influencing　mechanism　of　stirrup-confined　action　on　failure　behavior　and　size　effect　of　high-strength　RC　columns　under　small-eccentric　compressive　loading　was　revealed.　One　can　conclude　from　the　results　that:　1)　the　size　effect　exists　in　the　nominal　compressive　strengths　of　the　eccentrically　loaded　high-strength　RC　columns　with　the　present　four　different　stirrup　ratios;　2)　the　bi-logarithmic　plots　of　nominal　compressive　strengths　for　RC　columns　under　eccentric　loading　follows　closely　the　＇size　effect　law　(SEL)＇　proposed　by　Baant;　3)　the　presence　of　the　stirrup　confinement　changes　the　failure　patterns,　improves　the　nominal　strengths　and　makes　the　post-peak　behavior　of　columns　more　ductile,　and　finally　it　weakens　the　corresponding　size　effect;　4)　a　meso-scale　numerical　method　conducted　presents　the　mechanical　behavior　of　eccentrically　loaded　RC　columns　well.　©　2017,　Science　Press.　All　right　reserved.