▎ 摘　　要

NOVELTY - Preparing graphene heat conducting sheet comprises e.g. mixing graphene nanosheets powder and coal tar powder having high softening point pitch, then adding anhydrous ethyl alcohol, carrying out an ultrasonic process, filtering, adding mixed powder into a mold machine, carrying out cold laminating, placing slice which is interposed between smooth surface high temperature alloy in a tube furnace, in nitrogen or helium atmosphere, heating constantly at 420-450 degrees C for 0.5-1.5 hours in a rate of 3-5 degrees C/minute, and cooling to room temperature, to obtain graphene flakes of thickness 179-211 mu m. USE - The method is useful for preparing graphene heat conducting sheet (claimed). ADVANTAGE - The method has easy preparation procedure, and is suitable for industrial production. DETAILED DESCRIPTION - Preparing graphene heat conducting sheet comprises (i) mixing graphene nanosheets powder and coal tar powder having high softening point pitch in a mass ratio of 5:0.5, to obtain graphene nanosheets powder and coal tar mixed powder, then adding anhydrous ethanol, carrying out ultrasonic process for 0.5-2 hours, filtering, and drying, to obtain mixed powder, where the anhydrous ethanol and graphene powder are mixed in a mass ratio of 1 g:350-500 ml; (ii) adding step (i) mixed powder into a mold machine having hydraulic pressure of 15-20 MPa for 3-5 minutes, carrying out cold laminating to obtain slice; (iii) placing the step (ii) product which is interposed between smooth surface high temperature alloy in a tube furnace under hydraulic pressure of 5 MPa, under nitrogen, argon or helium atmosphere, heating constantly at 420-450 degrees C for 0.5-1.5 hours at a rate of 3-5 degrees C/minute, again heating constantly at 500-800 degrees C for 1-3 hours at a rate of 1-5 degrees C/minute, where the pressure of high-temperature alloy having thermal expansion under self boosting system is 21-34 MPa, and cooling to room temperature, to obtain graphene flakes having thickness of 179-211 mu m.