Ammonia　is　an　important　chemical　for　synthesized　fertilizers　traditionally　and　for　a　potential　energy　vector　increasingly.　Industrial　ammonia　synthesis　through　the　Haber-Bosch　process　is　energy-intensive　and　requires　advanced　materials　to　catalyze　ammonia　synthesis　under　mild　conditions,　whereas　the　utilization　of　ammonia　as　a　hydrogen　carrier　via　ammonia　decomposition　is　facing　a　similar　situation　as　well.　The　developed　second-generation　Ru-based　catalysts　performs　superior　activities　over　commercial　Fe-　or　Ni-based　catalysts;　however,　it　remains　challenging　to　construct　effective　Ru　catalysts　to　achieve　the　usage　of　Ru　metal　affordably　as　well　as　further　understanding　the　nature　of　Ru　catalysis.　This　Perspective　summarizes　the　recent　contributions　in　engineering　Ru-based　catalysts　via　various　strategies　and　related　catalysis　in　ammonia　synthesis　and　decomposition,　and　it　discusses　the　similarities　and　differences　of　Ru　catalysis　in　these　reactions.　Finally,　an　overview　of　this　area　and　opportunities　for　further　investigation　are　also　provided.　©　2022　American　Chemical　Society.　All　rights　reserved.