TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The wetting agent is ethanol, glycerin, sodium dodecyl benzene sulfonate, phenylacetic laurate alcohol ester, poly-dimethyl siloxane and/or dimethyl silicon oil, at 0.05-10 (preferably 0.5-5) wt.%. The protective layer is polymethyl methacrylate, polyethyl methacrylate, propyl methacrylate, isobutyl methacrylate, polydiphenylsiloxane, polydimethylsiloxane, polyethylene glycol terephthalate, polyimide, and one or the thick of at least two of natural rubber. The electrolyte is electrolyte and/or at least two of weak electrolyte, preferably ammonium sulfate, and/or potassium sulfate and nitric acid; electrolyte preferably initiator as water solution; and voltage of 1V-60 (preferably 5-15) V. The acidic solution comprises acid, oxidant and water, comprising sulfuric acid-hydrogen peroxide (H2O2)-water (H2O), nitric acid (HNO3)-H2O2-H2O, hydrochloric acid (HCl)-perchloric acid (HClO4)-H2O, HCl-H2O2-H2O (preferably); and acid, oxidant and volume ratio of water is 1:1:30-1:2:8, preferably 1:1:28-1:1:8. The cleaning solution is alkaline solution comprising alkali, oxidant and water, comprising ammonium hydroxide (NH4OH)-H2O2-H2O (preferably), sodium hydroxide (NaOH)-H2O2-H2O, and potassium hydroxide (KOH)-H2O2-H2O; volume ratio of oxidant and water is 1:1:40-1:5 (preferably 1:1:10-1:1:30); and washing using alkaline solution and/or advanced acidic solution, and carrying out alkaline cleaning solution comprising acidic solution. The reagent comprises acetone, chloroform, methylene dichloride, cyclohexane, ethyl acetate, petroleum ether, and ether; and the dopant is nitric acid, sulfuric acid and/or hydrochloric acid. Preferred Processes: The method further comprises growing surface of graphene thin film on metal substrate to form protection layer, applying voltage to electrolyte, and coated protective layer of graphene thin film peeling off from metal substrate, and adding wetting agent to obtain coated protective layer of graphene thin film; using cleaning solution to wash, obtaining graphene thin film as coated protective layer, putting protective layer graphene film to target substrate, removing protective layer of graphene thin film surface, and doping dopant to graphene thin film. The baking temperature is 40-200 (preferably 180) degrees C; and roasting time is more than 20 (preferably 40) minutes.