FIELD: petroleum processing. SUBSTANCE: hydrodesulfurization process accompanied with skeletal isomerization and reduced degree of hydrogenation of olefins contained in hydrocarbon mixtures is carried out in one step in presence of catalytic system including (i) acid-nature carrier constituted by X-ray-amorphous silica/alumina gel with silica/alumina molar ratio between 30: 1 and 500:1, which has specific surface 500 to 100 sq.m/g, porosity 0.3-0.6 ml/g, and pore diameter between 10 and 30 angstrom; (ii) mixture of VIB and VIII-group metals precipitated on carrier in summary amount from 2 to 67 % of the total weight of catalyst. Catalytic composition and a method for preparation thereof are also claimed. EFFECT: simplified hydrocarbon refining process. 26 cl, 13 tbl, 15 ex
