Reversible nitrogen absorption and desorption cycle of CeFe7 and Ce2Fe17 was performed by heating in NH3 or N-2 for nitrogenation and in H-2 for denitrogenation. The nitrogen absorption and desorption rates for CeFe7 were faster than that for Ce2Fe17 owing to the high diffusion rate of nitrogen for CeFe7, resulting that the nitrogen absorption and desorption property of CeFe7 was superior to that of Ce2Fe17.