FIELD: chemical industry. SUBSTANCE: catalyst carrier is based on particles of at least one (co)polymer of alpha-olefin(s) which have average particle size from 5 to 350 mcm, and pore volume formed by radius pores from 1000 to 75,000A is at least 0.2 cubic cm/g. Polymeric carrier is prepared by (co)polymerization of one or more alpha- olefins using catalyst system (s) comprising catalyst compound (a) and activator selected from organoaluminium compounds. Compound (a) is prepared by heat treatment in the presence of halogen-containing agent, liquid substance which is essentially product of reaction of titanium tetrachloride pretreated with electronic donor compound with composition (D) of general formula: AlRp(Y)gX3-(p+g) (II) wherein R is hydrocarbon radical; Y is OR′ wherein R′ is hydrocarbon radical; X is halogen; p is any integer such that 0<p≤2,5; g is any integer such that 0,5<g<3. Sum of (p+g) is such that 0,5<(p+g)≤3. Said heat treatment causes formation of solid particles. Method of preparing said compound comprises polymerizing one of more alpha-olefins using catalyst system (s) comprising catalyst compound (a) and activator selected from organoaluminium compounds. Catalyst compound (a) is prepared by above-mentioned procedure followed by treatment with composition (D). Also described are catalyst and method of polymerization of alpha-olefins. EFFECT: more efficient preparation method and more efficient polymerization method. 22 cl, 13 ex, 4 tbl
