Concrete frame structure in epicenter region has greatly damaged by Wenchuan Earthquake, especially short columns. Plenty of means for reinforcing these structures have been used. Finite element software ANSYS is used to simulate mechanical properties of structures after reinforced by broaden-section under monotonic or cyclic load. Comparison of frame’s horizontal displacement, crack of bearing carrier and distribution of node’s shearing stress etc. before and after reinforcing, it proves that broaden-section method is feasible in reinforcing of frame structure. Most of all, it verifies that broaden-section method has better reliability on reinforcing of RC frame’s short column.