To study the size effect on column flexural behavior, a 4170mm height reinforced concrete bridge column specimen and a 3/4 replica model are tested under quasi-static reversed cyclic loading. The structural force-displacement curve, sectional moment-curvature curve, lateral displacement due to bar slip and cyclic energy dissipation are compared based on dimensional principle. The analysis results show that, the structural lateral load and envelope curves of sectional moment-curvature relations exhibit similar response. However, because of lateral displacement due to bar slip, the maximum lateral drift of replica model is larger than that of the original specimen and the amount of energy absorption verse drift ratio is lower for replica model. Furthermore, the flexural component and bar slip component of lateral deflection at the top of the columns are computed from simplify curvature distribution curve and reinforcement slip model. Finally, the research findings are synthesized into a suggested expression that can be used to estimate displacement ductility under size effect.