A method of preparation of nucleated semi-crystalline polyolefin during coordination α-olefin polymerization, wherein an inorganic nucleating agent is treated with a surface active agent based on tertiary aliphatic amines of general formula: wherein R 1 represents C 12 -C 22 alkyl attached directly to nitrogen -(CH 2) 11-21 -CH 3 or through the carbonyl group -CO-(CH 2) 11-21 -CH 3, R 2 and R 3 represent -OH, -COOH, -CO-alkyl, while x and y are integers of 2 to 5 independent on each other or organic_nucleation agent is modified by an organoaluminium and dosed into a polymerization reactor as a component of catalyst system for α-olefin polymerization in form of a suspension in a non-polar hydrocarbon solvent or in form of a suspension or a solution in a concentrated organoaluminum, wherein a nucleating agent is an inorganic substance selected from a group involving talc, CaO, MgO, TiO 2, silica (SiO 2), alumina (Al 2 O 3), clay, graphite and carbon nanotubes, and wherein an organic nucleating agent is of non-sorbitol type selected from a group of compounds of general formula (I.a-d): wherein R 1, R 2 and R 3, or X 1, X 2 and X 3, or Y 1, Y 2 and Y 3, or Z 1, Z 2 and Z 3 independently represent: C 1 -C 20 alkyl unsubstituted or substituted by one or more hydroxy; C 2 -C 20 alkenyl unsubstituted or substituted by one or more hydroxy; C 2 -C 20 alkyl interrupted by oxygen or sulphur; C 3 -C 12 cycloalkyl unsubstituted or substituted by one or more C 1 -C 20 alkyl; (C 3 -C 12 cycloalkyl)-C 1 -C 10 alkyl unsubstituted or substituted by one or more C 1 -C 20 alkyl; branched C 3 -C 20 alkyl unsubstituted or substituted by one or more hydroxy; phenyl unsubstituted or substituted by one or more radicals selected from C 1 -C 20 alkyl, C 1 -C 20 alkoxy, C 1 -C 20 alkylamino, di(C 1 -C 20 alkyl) amino, hydroxy and nitro; phenyl-C 1 -C 20 alkyl unsubstituted or substituted by one or more radicals selected from C 1 -C 20 alkyl, C 3 -C 12 cycloalkyl, phenyl, C 1 -C 20 alkoxy and hydroxy; biphenyl-(C 1 -C 10 alkyl) unsubstituted or substituted by one or more C 1 -C 20 alkyl; naphthyl unsubstituted or substituted by one or more C 1 -C 20 alkyl; naphthyl-C 1 -C 20 alkyl unsubstituted or substituted by one or more C 1 -C 20 alkyl, or according to a general formula (II.): wherein k is an integer of 3 or 4; R 1 is a residue obtained by removing all of the carboxyl groups from 1,2,3-propanetricarboxylic acid, 1,2,3,4-butanetetracarboxylic acid or 1,3,5-benzenetricarboxylic acid; and the three or four R 2 s are the same or different, and each independently represents a hydrogen atom or a C 1 -C 10 linear or branched alkyl group, or compounds of general formula (III.a-c): X 2 -NHCO-X 1 -CONH-X 3 (III.a) Y 2 -CONH-Y 1 -NHCO-Y 3 (III.b) Z 2 -CONH-Z 1 -CONH-Z 3 (III.c) wherein X 1 or Y 1 or Z 1 independently represent: unsubstituted linear C 2 -C 20 alkyl; unsubstituted linear C 2 -C 20 alkenyl; C 3 -C 12 cycloalkyl; phenyl; biphenyl; naphthyl and X 2, X 3 or Y 2, Y 3 or Z 2, Z 3 independently represent: C 3 -C 12 cykloalkyl unsubstituted or substituted by one or more radicals selected from C 1 -C 20 aliphatic alkyl, C 3 -C 20 branched alkyl, C 2 -C 20 aliphatic alkenyl, C 3 -C 20 branched alkenyl, C 3 -C 12 cycloalkyl and phenyl; phenyl unsubstituted or substituted by one or more radicals selected from C 1 -C 20 aliphatic alkyl, C 3 -C 20 branched alkyl, C 2 -C 20 aliphatic alkenyl, C 3 -C 20 branched alkenyl, C 3 -C 12 cycloalkyl and phenyl.