FIELD: catalysts for petrochemical processes. SUBSTANCE: invention provides method for preliminary sulfonation of porous particles of catalyst containing at least one metal or metal oxide, which involves impregnation of catalyst with solution containing inorganic polysulfide ions having general formula S(x)2, wherein X is integer equal to at least 3, to give sulfur-containing catalyst, in which at least part of sulfide or sulfur is introduced into pores. Catalyst is then heated in presence of non-oxidizing gas: nitrogen, carbon dioxide, argon, helium, or their mixtures. EFFECT: facilitated preparation of catalyst. 8 cl, 2 tbl, 4 ex
