The invention relates to the technical field of preparation of nuclear fuel pellets, and particularly discloses to a method for preparing a uranium nitride pellet. The method comprises the following steps: 1, preparing a hydrogenation-dehydrogenation sample; 2, performing hydrogenation-dehydrogenation to prepare uranium powder; 3, preparing uranium sesquinitride powder; 4, molding a uranium sesquinitride green body; step 5, sintering the green body to form the uranium nitride pellet. The uranium nitride pellet obtained by the method has good surface appearance, and the density and the chemicalcomposition of the pellet meet the requirements of technical indexes, so the pellet can be used in a novel nuclear reactor to improve the core power density and reduce the release of fission products.