The invention discloses a preparation method of attapulgite catalyst of load phosphorus element and application of attapulgite catalyst in reforming and generating oil-removed trace olefin. The preparation method comprises steps of acidizing attapulgite by inorganic acid, obtaining attapulgite acidized by inorganic acid, and performing suction filtration and drying; steeping the dried acidized attapulgite by phosphoric acid with certain concentration to perform modified treatment; adding the molding assistant to the modified attapulgite, and then shaping, drying, and roasting; finally, obtaining the catalyst. The catalyst prepared by the invention has the advantages of replacing the existed attapulgite catalyst under the condition of not changing an acidized attapulgite deolefination device, and removing trace olefin reformed and generated to be oil; the catalyst is simple in preparation technique, low in cost, short in reaction time, and high in percent conversion; the catalyst life is more than 10 months, and is 2-3 months more than the service life of the acidized attapulgite.