In　the　engineering　structures　using　circular　steel　tube　(CST),　the　eccentric　loading　of　CST　members　often　occurs　due　to　installation　error　and　structural　form.　Existing　research　mainly　focuses　on　the　bearing　resistance　of　circular　steel　pipes　under　the　condition　of　eccentricity　at　one　end.　In　practical　application,　both　ends　of　CST　members　also　may　be　eccentric.　And　with　the　increase　in　eccentricity,　material　yielding　may　occur　prior　to　flexural　buckling.　So　far,　it＇s　lack　of　reports　about　the　mechanical　behavior　of　CST　members　subjected　to　eccentric　loading　at　both　ends　and　the　boundary　between　material　yielding　and　flexural　buckling.　This　paper　presents　experimental,　numerical　and　theoretical　studies　on　bearing　resistance　of　thin-walled　circular　steel　tube　with　slenderness　ratio　of　30,　40　and　50,　subjected　to　eccentric　loading　at　one　end　and　both　ends,　respectively.　The　study　reveals　a　significant　discrepancy　in　the　prediction　of　bearing　resistance　for　circular　tubes　subjected　to　eccentric　loading　at　both　ends　according　to　existing　design　codes.　Considering　the　synthesis　of　bending　moment　and　deflection　caused　by　eccentric　loading　at　both　ends,　the　calculation　method　of　the　bearing　resistance　based　on　flexural　buckling　of　CST　is　established,　which　enhances　the　prediction　accuracy　of　test　verification.　In　addition,　a　theoretical　boundary　between　the　two　failure　modes　appearing　in　CST　members　under　eccentric　loading　at　one　and　both　end(s)　-　flexural　buckling　and　reaching　the　material　yielding　strength　-　was　established　as　dominated　by　the　slenderness　ratio　and　loading　eccentricity.