Flexible structures such as tall buildings and chimneys can be regarded as cantilevers withbending and shear deformation. A deflection approach for damage identification of cantilev-er-type structures by using the vibration modes is proposed in this paper. An important ad-vantage of the approach is that the number of modes required is small, so it is easy for practi-cal application. The effectiveness of the approach is verified by numerical and experimental ex-amples .