The technique of numerical definition of distribution of tensions and deformations at harmonious loading and own frequencies of flat rubber shock-absorbers using computer program of modelling multiphysical processes " COMSOL Multiphysics 3.3" is offered. Dependence of rigidity of the shock-absorber on frequency of external axial harmonious loading, the Puason coefficient and thickness of a rubber layer is researched. It is determined: increasing value of Puason coefficient of rubber and decreasing thickness of a rubber layer, shock-absorber rigidity increase (figures 16-18); changes of values of Puason coefficient of rubber substantially affect rigidity of shock-absorber with thin rubber layer (compare figures 16 and 17); in case of low frequencies of external axial harmonious loading exist linear dependence within maximal deformation of moving plate of shock-absorber and amplitude of external force, but in case of high frequencies the dependence is not linear (figure 19); if frequency of external axial harmonious loading is getting closer to own frequencies of shock-absorber, then rigidity of shock-absorber is decreasing (figures 20 and 21).