In　the　laboratory　and　the　side　draw　test　unit　of　a　commercial　ammonia　synthesis　reactor,　the　performance　of　the　FA-Ru　catalyst　and　the　A202　iron　catalyst　was　compared,　and　the　influence　of　the　iron　catalyst　coupled　with　ruthenium　catalyst　and　the　single　iron　catalyst　on　ammonia　synthesis　was　investigated.　Experiment　results　showed　that　the　activity　of　the　FA-Ru　catalyst　for　ammonia　synthesis　was　higher　than　the　A202　catalyst　by　44%-75%　at　low　temperature　(375-425°C),　low　pressure　(10-15　MPa),　low　H2/N2　ratio　and　high　concentration　of　ammonia　synthesis　gas　(10%-16%,　vol)　in　the　laboratory.　Ammonia　conversion　was　higher　than　that　of　the　single　iron　catalyst　by　24.5%-44.8%　and　increased　with　increasing　ruthenium　catalyst　loading　in　mixed　catalyst　bed　under　laboratory　condition.　Similarly,　ammonia　conversion　was　higher　than　that　of　the　single　iron　catalyst　by　27.7%-58.8%　and　increased　with　increasing　ruthenium　catalyst　loading　in　tandem　with　iron　catalyst　under　laboratory　condition.　The　reaction　temperature　of　ruthenium　catalyst　bed　might　be　lowered　to　400°C　when　ruthenium　catalyst　loading　reached　above　half　of　the　iron　catalyst.　Side　draw　experiments　showed　that　ammonia　conversion　of　FA-Ru　catalyst　at　13.0　MPa　and　10000-15000　h-1　might　achieve　the　level　of　the　single　iron　catalyst　at　26　MPa　for　the　same　space　velocity.　Ammonia　conversion　of　iron　and　ruthenium　catalysts　in　tandem　was　43%-56%　higher　than　that　of　the　single　iron　catalyst,　depending　on　the　operation　condition.