A Pt-Sn/gamma-Al2O3 bifunctional catalyst was modified by tin, bismuth and tellurium using metal adsorption technique. The parent and the modified catalysts were tested in n-octane reforming under conditions similar to industrial applications. The added tin decreased the reformate yield a little, the aromatic content decreased and the isoparaffin content increased, the research octane number remained high. Tellurium and bismuth deposited greatly deactivated the metal function of the catalyst; the liquid yield of the product is far less than that over the parent platinum-tin catalyst. The isoparaffin and aromatic selectivity however changed favourably. More isoparaffin hydrocarbon was found in the liquid product over the modified catalysts. The reforming function of the metal was suppressed and, therefore, the reactions of alkenes occurring on the acid sites of the catalyst became dominant.