Ru/MgO-CeO2　catalysts　were　prepared　by　co-precipitation　with　different　precursors,　including　K2RuO4,　Ru(Ac)(3),　and　RuCl3,　the　obtained　catalysts　were　characterized　by　X-ray　diffraction,　X-ray　fluorescence,　N-2　physisorption,　temperature-programmed　reduction,　and　CO　chemisorption.　The　results　showed　that　the　ammonia　synthesis　activity　of　the　Ru/MgO-CeO2　catalyst　prepared　with　K2RuO4　was　16.0%　at　10　MPa,　450　degrees　C,　and　10　000　h(-1),　which　was　higher　than　those　obtained　with　the　other　two　precursors.　The　turnover　frequency　(TOF)　of　the　Ru/MgO-CeO2　catalyst　prepared　with　K2RuO4　was　higher　than　those　obtained　with　the　other　precursors　under　the　same　reaction　conditions.　The　influence　of　precursors　and　preparation　methods　on　the　structure　and　performance　of　the　catalysts　was　studied.　The　ratio　of　Ru/MgO-CeO2　catalysts　prepared　with　K2RuO4,　Ru(Ac)(3),　and　RuCl3　as　precursors　for　ammonia　synthesis　turnover　frequency　is　1.33:1.05:1　under　10　MPa,　425　degrees　C,　and　10　000　h(-1).