The invention relates to a preparation method of a high-porosity stepped hole carbon material cigarette filter tip additive. The preparation method is characterized by comprising the following steps: performing partial hydrolysis on tobacco stems under the action of solid acids, performing solid-liquid separation, loading mixed metal oxide on residues and carbonizing to obtain a metal oxide carbon material; adding the metal oxide carbon material into a filtrate, performing hydrothermal carbonization and then pickling and washing to obtain the high-porosity stepped hole carbon material cigarette filter tip additive. As the material is added into a cigarette filter tip, the effect of reducing the benzo(a)pyrene and tar in cigarette mainstream smoke is significant. The preparation method provided by the invention has the advantage that organic acids generated in the solid acid catalyzed cellulose hydrolysis process react with alcohols to form esters, so that the corrosion problem of the organic acids to a reactor can be solved. Wet-process dipping hydrolysis filter residues are conducive to the dispersion of metal components; metal-supported filter residue carbon can further promote the carbonization of hydrolysates in the filtrate, so that the yield of carbon products is increased.