The invention discloses a (1R, 5R)-(-)-3-arylmethylene nopinone ultraviolet absorbent and a preparation method thereof. The ultraviolet absorbent is (1R, 5R)-(-)-3-(4'-hydroxylbenzylidene) nopinone, (1R, 5R)-(-)-3-(4'-hydroxyl-3'-methoxylbenzylidene) nopinone, (1R, 5R)-(-)-3-(2'-hydroxyl-3'-methoxylbenzylidene) nopinone, (1R, 5R)-(-)-3-(4'-chlorobenzylidene) nopinone or (1R, 5R)-(-)-3-(furan-2'-ylbenzylidene) nopinone. The preparation method of the ultraviolet absorbent comprises the following steps: beta-pinene which is cheap and easy to get is taken as a raw material; nopinone with a bicyclic structure similar with that of camphor is obtained through selective oxidation; and the aldol condensation is carried out on the nopinone and aromatic aldehyde with a different structure so as to synthesize the ultraviolet absorbent. The preparation method has the advantages of simple synthetic route, simplicity and convenience, and economy for operating, high yield, little pollution and the like, and the defect that the camphor has long synthetic route, and high cost and the like is overcome. The synthesized ultraviolet absorbent has the advantages of good ultraviolet absorption effect, wide range of ultraviolet absorption spectrum and good stability and the like, and thus, the ultraviolet absorbent can have an excellent application prospect in ultraviolet absorption.