Modification of Ru/CeO₂ catalysts for NH₃-synthesis from H₂ and N₂ is of emerging interest for potential industrial application. Herein, we report an effective strategy by introduction silica to enhance ammonia synthesis performance by tuning hydrogen adsorption-desorption property. Owing to the enhancement of Ru sites surrounded by oxygen atoms, ceria-supported Ru catalyst with SiO₂ adsorbs more hydrogen species, and the desorption and exchange of hydrogen species would also be accelerated. Therefore, the introduction of SiO₂ into Ru/CeO₂ catalyst can improve the NH₃-synthesis activity by more than 34% at 400 °C, and the catalyst with SiO₂ shows a lower activation energy and superior high-pressure effect for ammonia synthesis. These findings will open up a new avenue for the development of ammonia synthesis and also provide guidance for preparing highly efficient oxides-supported metal catalysts in a series of hydrogen-involving reactions.