NOVELTY - Preparing sulfur-doped graphene electrode involves mixing 1-100 milliliters of 95-98 wt.% concentrated sulfuric acid with 20-100 milliliters of 65-68 wt.% concentrated nitric acid at 0 degrees C and then stirring the mixed material for 5-50 minutes. The stirred material is added with 1-200 grams of crystalline flake graphite and then the obtained material is stirred to stop agglomeration. The obtained material is added with 10-200 grams of potassium chlorate at room temperature for 20-150 hours and then the obtained material is washed and flocculated with sodium hydroxide.    USE - Method for preparing sulfur-doped graphene electrode used in fuel cell as cathode material (claimed).    ADVANTAGE - The method enables to prepare sulfur-doped graphene electrode in cost-effective manner, with good conductivity, high catalytic activity and excellent stability.    DETAILED DESCRIPTION - Preparing sulfur-doped graphene electrode involves mixing 1-100 milliliters of 95-98 wt.% concentrated sulfuric acid with 20-100 milliliters of 65-68 wt.% concentrated nitric acid at 0 degrees C and then stirring the mixed material for 5-50 minutes. The stirred material is added with 1-200 grams of crystalline flake graphite and then the obtained material is stirred to stop agglomeration. The obtained material is added with 10-200 grams of potassium chlorate at room temperature for 20-150 hours and then the obtained material is washed and flocculated with sodium hydroxide. The washed material is dried at 20-80 degrees C for 2-10 hours and then the dried material is ground to obtain oxidized graphene. 10-400 Milligrams oxidized graphene is dispersed in 20-200 milliliters deionized water for 0.5-2 hours to obtain graphene dispersed liquid. The obtained liquid is added with sodium hydroxide aqueous solution and then the obtained material is kept in a reaction vessel at 100-200 degrees C for 2-24 hours. The reacted material is washed with acetone and ethyl alcohol repeatedly and then the washed material is dried at 30-120 degrees C for 2-96 hours under vacuum to obtain the sulfur doped graphene. The sulfur doped graphene is dissolved in a solvent and then the dissolved material is dispersed for 5-120 minutes. The dispersed material is coated on a clean glass carbon electrode surface after polishing and then the coated material is dried to obtain the desired product.