Abstract: The transverse struck of a simply supported beam caused by a rigid mass for  a dynamic substructure model was built and the dynamic controlling equations were derived from finite element theory, to solve which the Newmark implicit integration method was applied. Then, a dynamic substructure technique was presented and applied to solve the propagations of elasto-plastic waves. Considering the local elasto-plastic contact deformation between the rigid mass and the beam, the calculations of the propagations of elasto-plastic waves by the dynamic substructure technique, including the bending moment wave, the flexural wave, the transverse velocity wave and bending stress waves, show the reasonable results of the propagations of elasto-plastic waves, dispersion of bending waves and formations of plastic hinges by the comparisons of those from the three-dimensional finite element method and rigid-plastic theory. Therefore, the presented dynamic substructure technique can be applied reasonably to the propagation of elasto-plastic waves induced by the impact along a flexible beam.