The invention relates to a disulfonic acid ester compound for preparing an olefin polymerization catalyst. The disulfonic acid ester compound is shown in the general formula (I), wherein A and B are carbon or hetero atoms selected from nitrogen, oxygen, sulfur, silicon, boron and phosphorus, R1-R6 and R1-R2n groups are C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 aralkyl or alkaryl, C2-C20 alkylene, C6-C20 condensed-ring aryl and C1-C20 esteryl of the same or different hydrogen and halogen or substituted or unsubstituted linear chains or branched chains, R1 and R2 are not hydrogen, R3-R6 and R1-R2n groups optionally comprise one or several hetero atoms used as carbon atoms or hydrogen atoms or substitutes of the carbon atoms and the hydrogen atoms, the hetero atoms are selected from nitrogen, oxygen, sulfur, silicon, boron, phosphorus or halogen atoms, one or more of R3-R6 and R1-R2n groups can be connected to form a ring, and n is an integer in a range of 0-10.