Although　ammonia　is　widely　recognized　as　one　of　the　most　promising　candidates　for　hydrogen　storage　and　transformation,　the　catalytic　mechanisms　involved　in　ammonia　decomposition　remain　insufficiently　understood,　and　the　stability　of　catalysts　continues　to　present　significant　challenges.　In　this　study,　Ru/CeO2-CNTs　catalysts　with　double　defect　sites　were　synthesized　by　a　straightforward　method,　achieving　an　outstanding　hydrogen　production　rate　of　2230　mmol-1　gRu-1　min-1　at　500　degrees　C,　outperforming　most　Ru-based　catalysts.　Experimental　characterization　and　theoretical　calculations　revealed　that　the　CeO2-CNTs　interface　promotes　the　formation　of　oxygen　vacancies　(Ov)　and　carbon　defects　(Cd)　through　carbon-oxygen　interactions.　These　defects　enhance　electron　transfer　from　the　support　to　Ru　nanoparticles　(NPs),　modulate　NH3　adsorption　and　activation　and　modulate　the　recombination　and　desorption　of　adsorbed　N　species　(N*).　Moreover,　the　coating　of　CeO2　significantly　improved　the　stability　of　CNTs,　which　weakens　undesired　reactions　under　high-temperature　and　hydrogen-rich　conditions.　The　study　introduced　a　rational　design　strategy　that　enhances　the　multiple　elementary　stages　of　the　NH3　decomposition　by　constructing　double　defect　sites　and　offering　new　insights　into　the　design　of　efficient　and　durable　catalysts　under　harsh　environments.