Abstract: In this paper, the uranium-zirconium hydride transient experimental device was used for the study of the physical characteristics of a new nuclear reactor power system. A new transient computational code was developed, for simulation of the experimental processes of the uranium-zirconium hydride transient experimental device, which was combined point-reactor kinetic equation with heat transfer equation and thermoelastic kinetic equation. Taking Health Physics Research Reactor (HPRR) as an example, the power, reactivity, temperature and radial displacement of HPRR over time were simulated with the developed code. The results of the code are consistent with the results of Fuchs-Hansen model, which verifies the correctness of the transient computational code.