NOVELTY - Preparation of graphene-coated metal nanoparticle catalyst includes taking carbon carrier, iron source and nitrogen source, dispersing in mixed solution of water and ethanol, stirring the mixed solution, adding EDTA disodium salt and methanol, hydrothermally reacting, water washing until neutral, filtering, drying, obtaining iron (Fe)-nitrogen (N)-carbon nanotube (CNT)-EDTA composite material, putting under inert atmosphere, high temperature processing, and obtaining the product.    USE - Preparation of graphene-coated metal nanoparticle catalyst used as proton exchange membrane fuel cell, alkaline anion exchange membrane fuel cell, metal air battery and cathode oxygen reduction reaction catalysts (all claimed).    ADVANTAGE - The method uses low cost raw materials with wide sources, has high yield, reduces production cost of fuel cell, provides catalyst with controllable iron and nitrogen content, low cost, high catalytic activity, good stability, strong methanol resistance and large specific surface area, and overcomes the easy agglomeration problem of metal nanoparticles.    DETAILED DESCRIPTION - Preparation of graphene-coated metal nanoparticle catalyst comprises taking carbon carrier, iron source and nitrogen source, dispersing in mixed solution of water and ethanol, where carbon carrier concentration is 3.33-16.67 g/L, concentration of iron source is 0.003-0.006 mol/L, concentration of nitrogen source is 0.013-0.039 mol/L, water and ethanol volume ratio is 1:1-3:1, the carbon carrier is CNT, carbon black, graphite and graphene oxide, the nitrogen source is dicyandiamide, melamine or ammonia water, and the iron source is ferric chloride, ferrous sulfate, or ferric ammonium sulfate, stirring the mixed solution at 25-50 degrees C for 1-3 hours, adding EDTA disodium salt and methanol, hydrothermally reacting at 120-180 degrees C for 3-24 hours, water washing until neutral, filtering, drying at 50-100 degrees C for not less than 5 hours, obtaining Fe-N-CNT-EDTA composite material, putting under inert atmosphere, high temperature processing at 500-900 degrees C for 1-5 hours, and obtaining the product.