Abstract: Based on the single process of hydrogenation-dehydrogenation, a new cyclical hydrogenation-dehydrogenation technology of Zr-2 alloy powder preparation was studied. The effects of hydrogenation temperature and pressure on hydride phase transition were investigated, and the effects of cycle number on hydrogenation-dehydrogenation process, ZrH and Zr structure, and powder productivity were investigated. The influence mechanism of hydrogenation-dehydrogenation process on crack propagation was discussed. In the results, the optimum hydrogenation temperature is 600 ℃, the optimum hydrogenation pressure is 0.3 MPa, and the optimum cycle number is 2 times. Cyclical hydrogenation-dehydrogenation is a dynamic equilibrium process between two hydrogenation-dehydrogenation processes, twice cycle can reach an optimum point. In addition, the impurity controlling can meet the requirement.