Ammonia is mainly consumed as a fertilizer in crop production and has attracted much attention as a promising candidate for a hydrogen carrier. The present findings will significantly promote the development of the energy-saving processes of ammonia synthesis. Commonly, most of Ru catalysts are supported on metal oxides or carbon materials. In the present catalyst, flat-shaped Ru nanoparticles with a uniform size distribution are distinctly anchored on the surface of Ca(NH2)2 by strong Ru?N interaction. As a result, Ru-loaded Ca(NH2)2 exhibits high catalytic performance and long term stability for ammonia synthesis under low reaction temperatures.