Few　studies　have　investigated　the　eccentric　compression　behavior　of　fiber-reinforced　polymer　(FRP)　confined　reinforced　concrete　(RC)　columns.　In　particular,　the　studies　on　the　eccentrically　loaded　large-sized　FRP-confined　RC　columns　are　limited.　In　this　study,　the　mechanical　responses　and　size　effect　behavior　of　FRP-confined　RC　square　columns　under　eccentric　loading　will　be　investigated　experimentally　and　numerically.　Nine　carbon　fiber-reinforced　polymer　(CFRP)　confined　columns　and　three　control　columns　with　cross-sectional　widths　(h)　from　200　to　600　mm　will　be　tested,　in　which　the　influence　of　the　structural　size　and　eccentricity　ratio　(e/h(0))　will　be　studied.　The　failure　patterns,　load-deflection　responses,　and　nominal　stress-strain　curves　of　CFRP　and　longitudinal　reinforcement　will　be　presented.　The　nominal　axial　strength　and　corresponding　lateral　deflection　of　tested　CFRP-confined　RC　columns　size　effect　existed.　Subsequently,　a　finite-element　(FE)　model　was　developed　and　verified,　in　which　the　mesoscale　structure　of　the　concrete　was　considered.　The　experimental　results　are　supplemented　by　FE　modeling　with　a　wider　range　of　structural　sizes　and　e/h(0).　In　addition,　the　predicted　equation　for　nominal　axial　strength　for　eccentrically　loaded　CFRP-confined　RC　columns　will　be　established,　of　which　the　accuracy　will　be　verified　by　comparison　with　the　experimental　and　numerical　data.