The invention discloses graphene/acrylic resin composite film and a preparation method thereof. The composite film comprises a composite film body, wherein the thickness of the composite film body is0.001-0.012 mm; the composite film body is formed by bonding and compounding modified graphene and modified acrylic resin, wherein the modified graphene is prepared by performing surface modificationand reduction on graphene oxide by mixing a silane coupling agent and alkyl-trimethyl-ammonium salt; the modified acrylic resin is at least prepared from, by weight, acrylic acid, methyl acrylate, polyester polyol, cyclodextrin, modified sepiolite fiber, initiator, a crosslinking agent and a plasticizer. The prepared graphene/acrylic resin composite film has the advantages of being ultra thin, good in stability, good in light transmittance, resistant to high temperature and resistant to curl, the antistatic value is increased greatly, and the requirements of being light, thin and convenient offlexible display screens and electronic products are fully met.