Structural health monitoring and damage localization is critical before localized damage in aerospace structures develops to the point where integrity and safety are jeopardized. For this purpose, structural damage was localized by the modal shape curvature method. The feasibility of the method was firstly verified by simulation calculations, and the sensitivity analysis of the modal shape curvature method was carried out by setting mode shapes with different signal noise ratios. Theoretical calculations show that the modal shape curvature method is sensitive to noise, and the accuracy of damage detection is affected when the signal noise ratio is low. Subsequently, the laser vibrometer combined with the modal shape curvature method is used to detect the damage of cracked beams with real crack-containing beams. In order to make the damage detection results more reliable, a damage threshold is defined based on the confidence level. The experimental results show that the laser vibrometer measurements have a high signal noise ratio, and the modal shape curvature method combined with the laser vibrometer can accurately locate structural damage with a confidence level of more than 99.9%.