The damage level of a reinforced concrete member which composes a structure becomes an index to evaluate the seismic performance of the structure. Therefore, the appropriate evaluation of the relations between the plastic deformation levels and the damage level of the member becomes necessary for reasonable seismic resistant design of the structures. In addition, it is necessary to evaluate quantitatively the ductility which represents the damage level. From this point of view, we carried out reversed cyclic loading tests using RC model columns with large deformational capacities and examined the influence of main parameters on the deformational capacities of the model columns. This paper presents quantitative evaluation of the ductility of RC column members.