Disclosed is a ruthenium-based catalyst for hydrogen production from ammonia decomposition, comprising an active component, a promoter and a carrier, wherein the active component is ruthenium, the promoter is cesium and/or potassium, and the carrier comprises magnesium oxide, an activated carbon, cerium oxide, molybdenum oxide, tungsten oxide, barium oxide and potassium oxide. The present invention further discloses a preparation method and application of the aforementioned ruthenium-based catalyst for hydrogen production from ammonia decomposition. Compared with the prior art, the ruthenium-based catalyst for hydrogen production from ammonia decomposition provided by the present invention is low in preparation cost and simple in process, and has high catalytic activity at low temperature and good heat resistance.