The effect of topography on generation of the solitary Rossby waves is researched.Here,the topography,as a forcing for waves generation,is taken as a function of longitude variable x and time variable t,which is called unstable topography.With the help of a perturbation expansion method,a forced mKdv equation governing the evolution of amplitude of the solitary Rossby waves is derived from quasi-geostrophic vorticity equation and is solved by the pseudospectral method.Basing on the waterfall plots,the generational features of the solitary Rossby waves under the influence of unstable topography and stable topography are compared and some conclusions are obtained. The effect of topography on generation of the solitary Rossby waves is researched. Here, the topography, as a forcing for waves generation, is taken as a function of longitude variable x and time variable t, which is called unstable topography .With the help of a perturbation expansion method, a forced mKdv equation governing the evolution of amplitude of the solitary Rossby waves is derived from quasi-geostrophic vorticity equation and is solved by the pseudospectral method. Basing on the waterfall plots, the generational features of the solitary Rossby waves under the influence of unstable topography and stable topography are compared and some connected are obtained.