Catalyst compound for preparing polyolefin for fibers, and preparation method and application thereof, catalyst system, application of catalyst system, and olefin polymerization method

The invention discloses a method for preparing a catalyst compound for preparing polyolefin for fibers, wherein the method comprises the steps: carrying out a first contact reaction of magnesium halide with an alcohol compound in the presence of a hydrocarbon solvent, to form a uniform solution; in the presence of a precipitation aid, carrying out a second contact reaction of the uniform solution with a titanium compound, to obtain a mixture containing a solid precipitate; and carrying out a third contact reaction of the obtained mixture with an internal electron donor compound d, to obtain a suspension, wherein the internal electron donor compound d is a 1,3-diether compound. The invention also discloses the prepared catalyst compound and an application thereof in a catalyst system, the catalyst system for preparing the polyolefin for the fibers, an application of the catalyst system in olefin polymerization reaction for preparation of a fiber material, and a polymerization method for preparing the polyolefin for the fibers. A polymer prepared by using the prepared catalyst compound has the advantages of narrow molecular weight distribution and high regularity, and is suitable for production of fiber-graded polypropylene.