The　Co/CeO2　catalysts　promoted　with　Ba　or　K　were　prepared　to　study　the　effect　of　promoter　on　the　catalytic　performance　of　ammonia　synthesis.　The　results　show　that　the　presence　of　Ba　or　K　promoter　changes　the　properties　of　CeO2-supported　Co　catalysts　including　the　surface　area,　the　crystallite　size　and　the　morphology　of　CeO2,　the　reduction　degree　of　cobalt　species　and　the　adsorption　performance　of　hydrogen　and　nitrogen.　As　a　consequence,　the　samples　promoted　with　an　appropriate　amount　of　Ba　show　higher　ammonia　synthesis　rates,　while　the　catalysts　with　high　Ba　loading　or　K　promoter　all　exhibit　low　catalytic　activities.　©　2018　Chinese　Society　of　Rare　Earths