To address the issue of low accuracy in local damage identification of beam structures based on modal parameters, a combined damage identification method integrating the theory of flexural wave propagation and wave theory is proposed. Firstly, the motion equation governing the flexural deformation of slender beams under the Bernoulli-Euler beam model is derived, and theoretical analysis of flexural wave propagation in the beam is conducted to obtain the wave propagation solution. Secondly, flexural wave in the beam is identified using wave theory. Finally, a damage index based on the relationship between beam stiffness and flexural wave velocity is constructed to identify structural damage, including its location and degree. The method is validated through numerical models and laboratory experiments, demonstrating it has good noise immunity.