The　ammonia　synthesis　was　performed　over　Ru　catalyst　supported　on　perovskite-type　BaZrO3.　Physiochemical　properties　of　this　catalyst　were　also　characterized　by　means　of　various　techniques　to　show　the　relationships　between　catalyst　structure　and　catalytic　performance.　It　was　found　that　the　ammonia　concentration　in　the　effluent　of　Ru/BaZrO3　catalyst　was　6.36%　at　673　K　under　3.0　MPa,　which　was　much　higher　than　that　of　Ru　catalyst　supported　on　other　supports　including　carbon　material　systems　under　the　similar　conditions,　and　the　rate　did　not　decrease　even　if　the　reaction　was　executed　for　120　h.　This　might　be　attributed　to　the　facts　that　the　optimum　size　of　Ru　particles　has　more　B-5-type　sites,　strong　electron-donating　ability　of　the　BaZrO3　support　and　the　strong　metal-support　interaction　provides　an　efficient　channel　for　electron　transfer.　On　the　other　hand,　the　adsorption　of　H-2　was　inhibited　over　the　surface　of　this　catalyst　and　the　number　of　active　sites　for　the　activation　of　N-2　was　also　increased.　(c)　2013　Elsevier　B.V.　All　rights　reserved.