The invention discloses a rapid preparation method and a product of a uranium dioxide/nano-diamond nuclear fuel pellet, and belongs to the field of energy and composite materials, particularly belongsto the field of powder metallurgy, and aims to solve the problems that safety requirements of a nuclear power station are difficultly met as heat conductivity of an existing ceramic uranium dioxide (UO2) pellet is poor. According to the method, the uranium dioxide/nano-diamond nuclear fuel pellet with a three-dimensional network structure is prepared by a powder metallurgy technique, the heat conductivity of uranium dioxide nuclear fuel is improved, high-temperature stability and radiation stability of the fuel pellet are improved, the method can effectively solves the problems, safety of theuranium dioxide nuclear fuel pellet is greatly improved, industrial large-scale production application requirements can be met, the method has high application value and good application prospect andis worthy of large-scale popularization and application.