Catalyst component for olefin polymerization and preparation method and application thereof

The invention relates to an olefin polymerization catalyst, and discloses a catalyst component for olefin polymerization and a preparation method and application thereof. The catalyst component comprises a magnesium element, a titanium element and an internal electron donor, wherein the internal electron donor comprises phosphate ester and alpha-cyano succinate and/or substituted alpha-cyano succinate, and the molar ratio of the phosphate ester to the magnesium element is (0.0002-0.002): 1. When the catalyst is used for olefin polymerization, especially propylene polymerization, an obtained polymer has the characteristics of relatively high Z + 1 average molecular weight and good rigidity-toughness balance. 本发明涉及烯烃聚合催化剂，公开了一种烯烃聚合的催化剂组分及其制备方法和用途。本发明的催化剂组分包括镁元素、钛元素和内给电子体；其中，内给电子体包括磷酸酯和α-氰基丁二酸酯和/或取代α-氰基丁二酸酯，磷酸酯与镁元素的摩尔比为0.0002-0.002:1。该催化剂用于烯烃聚合尤其用于丙烯聚合时，所得聚合物具有较高的Z+1均分子量、刚韧平衡性好的特点。