FIELD: polymerization catalysts. SUBSTANCE: olefin copolymerization catalytic system includes at least one ionic halogenated metallocene derivative with IV group transition metal, at least one solid catalytic substance containing titanium, magnesium, and chlorine, and at least one aluminum derivative with general formula AlXnT3-n, wherein X is halogen atom, T optionally oxygen-containing hydrocarbon radical, and n=0-3. In particular, substance contains 15-20% titanium, 0.5-20% magnesium, and 30-40% chlorine. Invention also provides precursor of catalytic system, method for preparation of the latter, and olefin copolymerization process. EFFECT: achieved preparation of polymers with broad molecular weight distribution, increased their apparent density, and eliminated process deposits in polymerization equipment. 26 cl, 5 ex
