▎ 摘　　要

NOVELTY - Ruthenium-based catalyst, comprises ruthenium supported on a carrier, and based on the total weight of the ruthenium-based catalyst the supported amount of ruthenium is 0.1-10 wt.%. USE - The ruthenium-based catalyst is useful in reaction of direct conversion of synthesis gas into olefins (claimed). ADVANTAGE - The catalyst: is easy to prepare, and easy to repeat; and has good stability; operates at lower temperature and pressure, utilizes less by-product of methane and carbon dioxide including less than 5% under the high single-pass carbon monoxide conversion rate and the rate is upto 50%, and has high selectivity of olefin up to more than 80%. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: preparing ruthenium-based catalyst, comprising (i) dissolving a soluble salt in the solvent corresponding to ruthenium to obtain a mixed solution, and (ii) mixing the mixed solution with the carrier, drying and carrying out calcination to obtain final product, where the ruthenium-based catalyst further includes an auxiliary agent, and the mixed solution also includes the soluble salt corresponding to the auxiliary agent; and use of catalyst comprising subjecting the ruthenium-based catalyst into reduction pretreatment before the synthesis gas is directly converted into olefins, directly converting the synthesis gas into olefins with hydrogen and carbon monoxide as reaction gases, the volume ratio of the hydrogen and carbon monoxide is 1:20-20:1, the reaction temperature is 200-350℃, the reaction pressure is 0.1-5 MPa, and the reaction space velocity is 1500-9000 h.-1