This paper aims to investigate the ductility behavior of partially concrete-filled steel box-section bridge piers by 2-D beam element formulation. Twenty beam element models are established,in which three parameters,the flange plate width-thickness ratio,slenderness ratio of steel piers and height of filled-in concrete are considered. The correction coefficient of ductility behavior obtained from 2-D beam element formulation is proposed by comparing the numerical results with 3-D accurate results. The modified 2-D simulation results are in line with the experimental results,which indicate that the proposed numerical method and the correction coefficient are accurate and valid enough. The increase of concrete filling rate can effectively improve the ductility of steel bridge piers. Increasing of the flange plate width-thickness ratio and slenderness ratio of steel piers will lead to a decline in steel pier ductility.