Ultrahigh-molecular-weight polyethylene (UHMWPE), with its excellent wear resistance and biocompatibility, has important application as artificial joints. The most commonly used method to improve its wear resistance is to introduce crosslinking through irradiation. However, free radicals are introduced after radiation, which are easy to cause inflammation in the human body. Some antioxidants, such as vitamin E (VE), need to be added. However, the addition of VE could reduce the crosslinking density of UHMWPE and worsen the wear resistance of the material. Therefore, obtaining new antioxidants that could eliminate free radicals without affecting or even improving the crosslinking density of materials during irradiation is an important subject worth exploring. In this paper, a kind of natural polyphenol substance, resveratrol (RSV), was introduced as a new antioxidant and crosslinking promoter during irradiation crosslinking of UHMWPE. RSV can better eliminate free radicals than VE and further improve the crosslinking density to obtain UHMWPE materials with excellent oxidation resistance and high wear resistance. The multi-active phenolic hydroxyl structure of RSV molecule provides its free-radical trapping ability, and the appropriate molecular size of RSV may promote the H-type crosslinking of UHMWPE, thereby increasing the crosslinking density. This work provides a new pathway for developing high-performance artificial joint prosthesis materials.