An evaluation method to predict the ductility capacity of reinforced concrete columns strengthened by wrapping carbon fiber sheet (CFS) is proposed. A series of cyclic loading tests were conducted for five circular reinforced concrete columns. Based on the existing 20 test results conducted by other researchers in addition to the 5 tests presented in this study, the fiber model specified in the Seismic Design Specifications of Highway Bridges 1995 was clarified for evaluating the ultimate displacement. The stress vs. strain model of concrete confined by both tie and CFS, which was developed by the first two authors, was used in the analysis. Introducing a modification factor for the rectangular columns, it is shown that the ultimate displacement for the 25 specimens can be satisfactorily predicted.