The influence of electron donors on the synthesis of polypropene-block-poly(ethene-co-propene) (PP-b-(PE-co-PP)) using a modified stopped-flow polymerization method was examined in terms of correlation of the microstructure of the polymer with its crystalline morphology. The results of propene homopolymerization and ethene-propene copolymerization indicated that the application of suitable internal and external donors induced an improvement in the stereoregularity of polypropene (PP) without a decrease in the initial activity and a significant change in the monomer composition and monomer sequence distribution of the poly(ethene-co-propene) (PE-co-PP). The TiCl4/ethylbenzoate/MgCl2 -cyclohexylmethyldimethoxysilane catalyst system was found to produce PP-b-(PE-co-PP) having highly isotactic PP segments. The resulting block copolymers were investigated by cross-fractionation chromatography and differential scannning calorimetry, suggesting that the improved stereoregularity of the PP part in the PP-b-(PE-co-PP) had an effect only on the crystallinity and crystallinity distribution but had no influence on the crystallizability and lamellar thickness of the block copolymer.