The invention relates to an olefin polymerization catalyst carrier. A general formula of the olefin polymerization catalyst carrier is Mg(OR1)n(OR2)2-n, wherein n is smaller than or equal to 2 and greater than or equal to 0; R1 and R2 can be the same or different, and are alkyl radicals of C1-C20; the olefin polymerization catalyst carrier is characterized in that a group of peaks exist within the range that a 2theta diffraction angle is 5-15 degrees in an X-ray diffraction pattern; and 1-4 diffraction peaks form a group. The carrier provided by the invention is smooth in surface, compact in structure, and good in mechanical strength; and the activity of the catalyst and the form of a polymer can be improved.