The utility model relates to an auxiliary screen vibratory threshing machine, which comprises a machine body, a threshing barrel, a rolling shaft and a main screen stencil. The utility model is characterized in that an exhaust port of a long grass steppe leaf of the main screen stencil is provided with the auxiliary screen stencil which is obliquely arranged; the high end of the auxiliary screen stencil is movably fixed on the machine body, and the lower end of the auxiliary screen stencil is a free end and is connected with a lever end; a fulcrum of the lever is arranged on the machine body, and the other end of the lever is connected with the roller shaft by a crank or an eccentric bearing. The auxiliary screen vibratory threshing machine of the utility model has simple structure; because the auxiliary screen stencil is obliquely arranged and the free lower end moves up and down under the action of the lever, the auxiliary screen stencil vibrates up and down, and the auxiliary screen vibratory threshing machine can thresh and discharge grass steppe coat well automatically even if the utility model is used on rainy days or is threshed with wet grass steppe. The utility model has the advantages of high work efficiency and safe use, and the grass steppe coat can be grabbed by a user's hand directly.