The invention discloses a method for preparing an olefin-removing catalyst, which is characterized by consisting of a high-silica alumina ratio ReUSY molecular sieve serving as a main active ingredient, a mordenite molecular sieve serving as a second active ingredient, and alumina serving as a binder. The preparation method comprises the following steps of: (1) uniformly mixing the high-silica alumina ratio ReUSY molecular sieve, the mordenite molecular sieve and the binder, wherein the binder component accounts for 5 to 80 percent of the total weight of the catalyst; (2) adding an extrusion assistant, a pore-expanding agent or a strength aid accounting for less than 5 percent, uniformly mixing, and adding dilute solution of inorganic acid or acetic acid for kneading; (3) extruding the mixture prepared in the step (2) into strips; and (4) roasting the strips prepared in the step (3) at the temperature of between 400 and 650 DEG C for 2 to 6 hours.