A method for interface modification of carbon/carbon composite material by graphene/polymer coating, relates to a carbon/carbon composite material modification method. The method aims to resolve the disadvantage that the modification carbon/carbon composite material prepared by existing interface modification methods could not endure high temperature. The method comprises the following steps: 1, oxidizing graphite to obtain oxidized graphite powder; 2, preparing a solution of oxidized graphene; 3, purification; 4, preparing the graphene; 5, preparing a graphene/polymer coating solution; 6, coating carbon fibers; 7, carbonization processing. The method is advantageous in that: 1, the operation is simple and the cost is low; and 2, interface properties of the carbon/carbon composite material prepared by the method are improved by 20-80%, macroscopic mechanical properties of the carbon/carbon composite material prepared by the method are improved by 3-30%, and ablation resistance properties of the carbon/carbon composite material prepared by the method are improved by 10-50%, compared with those of the untreated materials. The method is mainly used for preparing interface modification carbon/carbon composite materials.