Using a semi-spectral barotropic quasigeostrophic vorticity equation in the cylindrical coordinates,four experiments whose integration time is seven model hours are performed in order to study the propagation characteristics of vortex Rossby waves in different initial distributions of perturbation vorticity. Results show that propagation of vortex Rossy waves in an initial perturbation vorticity field of azimuthal wave-number 2(i.e positive alternating with negative) is obviously different from that in an intial field of only positive perturbation vorticity.The inward propagation vorticity decays more rapidly in the former case than in the latter case.And the inward propagation of vorticity exhibits a single peak form,but it shows a double peak form in the latter case.