Graphene normally has weak interface compatibility to organics. In this paper, the surface of graphene is modified in order to improve its compatibility with polymer matrixes. Therefore, a Silane Coupling Agent(SCA) γ-Glycidoxypropyltrimethoxysilane is used to modify graphene. The results of the TEM, FTIR and sedimentation test show that SCA grafting can improve the graphene’s dispersion stability in polar organic solvent. Then modified graphene is added to epoxy resin to obtain an epoxy resin composite. The conductivity of the epoxy resin compostie can reach 8.00E-009 s/m. When additional percentage of SCA is over 0.5%, the dielectric constant (ε) has a remarkable increase.