Concrete simple T beam finite element model through ANSYS is constructed to analyze the effect of the model on damaged structure identification in different damaged conditions and with the two methods such as flexibility curvature difference and dynamic response second order derivative difference.Flexibility curvature difference has higher accuracy on identifying real location of the damage but has little influence degree sensitivity to undamaged location.Dynamic response second order derivarive difference has much higher sensitivity to damaged degree but has low identification effect on real damaged lacation,thus,the combination of the two methods can better detect the damaged condition of the structure.