A method for producing sulfonated graphene from an organic material, the method comprising: a first contact step: contacting a reaction medium containing an oxidative sulfonating agent and an optional solvent with the organic material at a first temperature; and a second contact step: after the first contact step has been finished, in the same reaction medium, increasing the reaction temperature to a second temperature to continue to react, thereby obtaining the sulfonated graphene; wherein the oxidative sulfonating agent comprises at least one selected from the group consisting of: a compound having a general formula R-SO 3 H, wherein R is selected from the group consisting of F, Cl, and Br; a combination of H 2 SO 4 and HCl; a combination of H 2 SO 4 and HF; concentrated sulfuric acid; fuming sulfuric acid; and a combination thereof; wherein the organic material is selected from the group consisting of organic polymer materials and organic small molecular materials, preferably, the organic polymer material is selected from the group consisting of polyethylene wax, chlorinated polyethylene, acetylene oligomer, polyacetylene, polyalkyne containing a halogen element, polyethylene, polyvinyl chloride, polyalkenes containing a halogen element, and preferably, the organic small molecular material is selected from the group consisting of C 4 -C 50 linear hydrocarbons or aromatic hydrocarbons with a benzene ring structure; and wherein the first temperature is within a range from a melting temperature of the organic material to a boiling point of the reaction medium; and the second temperature is within the range of equal to or greater than the boiling point of the reaction medium. a first contact step: contacting a reaction medium containing an oxidative sulfonating agent and an optional solvent with the organic material at a first temperature; and a second contact step: after the first contact step has been finished, in the same reaction medium, increasing the reaction temperature to a second temperature to continue to react, thereby obtaining the sulfonated graphene; wherein the oxidative sulfonating agent comprises at least one selected from the group consisting of: a compound having a general formula R-SO 3 H, wherein R is selected from the group consisting of F, Cl, and Br; a combination of H 2 SO 4 and HCl; a combination of H 2 SO 4 and HF; concentrated sulfuric acid; fuming sulfuric acid; and a combination thereof; wherein the organic material is selected from the group consisting of organic polymer materials and organic small molecular materials, preferably, the organic polymer material is selected from the group consisting of polyethylene wax, chlorinated polyethylene, acetylene oligomer, polyacetylene, polyalkyne containing a halogen element, polyethylene, polyvinyl chloride, polyalkenes containing a halogen element, and preferably, the organic small molecular material is selected from the group consisting of C 4 -C 50 linear hydrocarbons or aromatic hydrocarbons with a benzene ring structure; and wherein the first temperature is within a range from a melting temperature of the organic material to a boiling point of the reaction medium; and the second temperature is within the range of equal to or greater than the boiling point of the reaction medium. <EOS>