NOVELTY - Preparing platinum/graphene catalyst, comprises: (a) extracting graphite and dispersing it in deionized water in ultrasound, adding chloroplatinic acid (2.66-15.93 parts) and uniformly mixing, reducing for 1-18 hours, filtering, washing with deionized water, drying for 6-24 hours at 60-100 degrees C; or (b) extracting graphite and dispersing it in glycol, adding chloroplatinic acid (2.66-15.93 parts) and uniformly mixing it, reducing for 3-12 hours at 90-150 degrees C, filtering and washing with deionized water, drying the product for 6-24 hours at 60-100 degrees C.    USE - The platinum/graphene catalyst is useful in proton exchange membrane fuel cells.    ADVANTAGE - The platinum/graphene catalyst obtained by the method, exhibits excellent electro-chemical properties when compared with the conventional platinum and graphene catalysts.    DETAILED DESCRIPTION - Preparing platinum/graphene catalyst, comprises: (a) sodium borohydride reduction method comprising extracting graphite and dispersing it in deionized water in ultrasound to form 1000-20000 parts of graphite oxide dispersion (0.05-1 wt.%), adding chloroplatinic acid (2.66-15.93 parts) and uniformly mixing it to obtain platinum/graphene catalyst (10-60 wt.%), adjusting the pH to 9-13 using potassium hydroxide solution (0.5-4 M) obtained by mixing potassium hydroxide (160-640 parts) and deionized water (5000-10000 parts), reducing for 1-18 hours, filtering, washing with deionized water, drying for 6-24 hours at 60-100 degrees C to obtain the platinum/graphene catalyst; or (b) glycol reduction method comprising extracting graphite and dispersing it in glycol to form 1000-20000 parts of graphite oxide dispersion (0.05-1 wt.%), adding chloroplatinic acid (2.66-15.93 parts) and uniformly mixing it to obtain the platinum/graphene catalyst (10-60 wt.%), adjusting the pH to 9-13 using potassium hydroxide solution (0.5-4 M), reducing for 3-12 hours at 90-150 degrees C, filtering and washing with deionized water, drying the product for 6-24 hours at 60-100 degrees C to obtain the platinum/graphene catalyst.