The invention relates to a gas demister of a slurry bed for hydrogenation of acetylene to ethylene. The demister is a hard wire mesh with the mesh number of 10-20, and a catalyst layer with the thickness of 0.5 mu m-20 mu m. By means of the catalyst layer arranged on the hard wire mesh, the demister not only prevents volatile components of solvents from evolving, but converts micro acetylene in reaction products completely, accordingly the conversion rate of catalytic reaction is greatly increased. In addition, the demister is simple in structure, small in size and high in demisting efficiency. A wire mesh block is detachable and easy to mount, operate, repair and clean. In the meantime, the wire mesh block is made of high-strength polytetrafluoroethylene, wear-resistant nylon 66 and polypropylene, thus the wire mesh is corrosion and high temperature resistant, the service life is prolonged, and costs are reduced.