A method has been developed for preparing UN by two-step reaction using UF4. As a result, the reaction of UF4 with Si and N2 has proved quite practical for obtaining U2N3. It was confirmed by chemical analysis and by X-ray diffraction analysis that single phase U2N3 was obtained at reaction temperatures above 1,200°C, and only 3% of the uranium was lost by evaporation even at 1,200°C. In the second reaction, the dissociation of U2N3 to UN in vacuum took place rapidly above 1,050°C, at which temperatures single phase UN was obtained, possessing a lattice constant of 4.888 A.