FIELD: chemistry of polymers. SUBSTANCE: method involves preparing polymers and copolymers of olefins of formula 
wherein R is hydrogen or alkyl having from 1 to 10 carbon atoms. The claimed method comprises at least one (co)polymerization stage in gas phase in the presence of highly active catalyst from reacting titanium compound with magnesium halide in active form as carrier and alkyl aluminium compound. The method is peculiar in that it occurs when feeding small amount of compound having at least two groups which are identical or different and capable of reacting with alkyl aluminium compound and selectively suppressing reactivity of polymer particles which are very fine as compared with average granulometric size of polymer present in gas phase. The method is simple easy to be carried out without decrease in the yield of the product and without retardation in the process course. EFFECT: more efficient preparation method. 11 cl, 3 dwg, 14 ex, 1 tbl
