NOVELTY - A catalyst layer formed using a catalyst slurry by screen printing process and a diffusion layer are laminated with a proton exchange membrane, such that the catalyst layer is placed between the diffusion layer and proton exchange membrane, to obtain membrane electrode. The solid content of catalyst slurry is 5-15 weight%.    USE - Preparation of membrane electrode used for proton exchange membrane fuel cell.    ADVANTAGE - Since the catalyst layer of uniform thickness is formed by screen printing process, the membrane electrode uniformly performs electrochemical reaction. The electrode has improved electricity generating performance.    DETAILED DESCRIPTION - A catalyst layer formed using a catalyst slurry by screen printing process and a diffusion layer are laminated with a proton exchange membrane, such that the catalyst layer is placed between the diffusion layer and proton exchange membrane, to obtain membrane electrode. The solid content of catalyst slurry is 5-15 weight%, preferably 7-13.5 weight%. The catalyst slurry contains catalyst, Nafion (RTM: sulfonated tetrafluoroethylene based fluoropolymer-copolymer) solution and solvent. The weight ratio of Nafion (RTM: sulfonated tetrafluoroethylene based fluoropolymer-copolymer) solution and solvent is 1:0.02-5. The catalyst is platinum/carbon, platinum-ruthenium/carbon and/or platinum-chromium/carbon. The solvent is water, isopropyl alcohol, ethanol and/or propanetriol. The Nafion (RTM: sulfonated tetrafluoroethylene based fluoropolymer-copolymer) solution comprises sulfonated tetrafluoroethylene based fluoropolymer-copolymer resin, lower alcohol and water in a weight ratio of 1:15-16:3-4. The diffusion layer is formed by coating conducting-agent slurry on a conducting substrate. The content of conducting agent in the slurry is 5-60 wt.%. The conducting-agent slurry contains cementing agent and solvent in weight ratio of 1:0.02-5. The conducting agent is active carbon, acetylene black and/or graphite carbon black. The cementing agent is polytetrafluoroethylene, hexafluoropropene and/or polyvinyl fluoride. The conducting substrate is carbon paper.