An　experimental　study　was　made　of　the　mechanical　properties　of　large　scale　confined　concrete　subjected　to　the　axial　compression　test.　Eleven　tied　concrete　columns　and　six　plain　concrete　prisms　were　tested.　In　the　test,　each　specimen　had　the　same　transverse　reinforcement　configuration,　and　similar　volumetric　ratio　of　lateral　steel,　while　different　size.　The　test　results　in　this　paper　indicate　that　the　size　of　the　specimen　has　no　obvious　relationship　with　the　ultimate　strength,　however,　it　does　affect　the　post-peak　ductility　to　some　extent.　As　a　supplement　to　the　experimental　study,　a　finite　element　method　was　adopted　to　imitate　the　mechanical　behavior　of　the　confined　concrete　under　axial　compression.　The　results　of　the　imitation　in　this　paper　indicate　the　confinement　mechanism　of　large　scale　specimens.