In　this　paper,　concrete　is　considered　a　three-phase　composite　material　composed　of　aggregate,　a　mortar　matrix,　and　an　interface　transition　zone　to　investigate　the　eccentric　compressive　behavior　of　corroded　reinforced　concrete　(RC)　columns　from　the　mesoscopic　perspective.　The　deterioration　of　the　material　properties　of　steel　bars,　concrete　cover,　and　bond　strength　was　considered　to　be　caused　by　corrosion,　and　a　three-dimensional　refined　finite　element　analysis　model　was　established.　The　numerical　results　are　in　good　agreement　with　the　experimental　results,　which　verifies　the　rationality　of　the　numerical　analysis　model.　The　effect　of　corrosion　level　and　eccentric　ratio　on　the　eccentric　performance　of　corroded　RC　columns　is　explored　and　discussed.　The　simulation　results　indicate　that　the　corrosion　of　steel　bars　increases　the　critical　eccentricity,　which　may　make　the　structure　tend　to　brittle　failure.　The　increased　corrosion　level　would　obviously　cause　a　reduction　of　stiffness,　ductility,　and　ultimate　bearing　capacity　of　the　columns.　In　addition,　increased　eccentricity　causes　a　reduction　in　axial　bearing　capacity,　and　the　failure　mode　of　columns　changes　to　large　eccentric　compression　failure.　Eventually,　based　on　the　unified　formula　for　the　bearing　capacity　of　RC　members　in　good　condition　and　in　consideration　of　the　influence　of　steel　corrosion,　a　calculation　formula　for　the　bearing　capacity　of　corroded　RC　members　was　developed.　The　accuracy　of　the　proposed　formula　was　verified　in　comparison　with　the　experiment　results.　©　2022,　Science　Press.　All　right　reserved.