The invention relates to a graphene modified composite piston, a preparation method and application thereof. The preparation method includes: adding graphene powder into an ethanol-acetone mixed solution, dispersing the powder uniformly, and then conduct ultrasound treatment; adding the obtained solution into a phenolic resin acetone solution, and mixing the substances evenly; firstly using precursor infiltration pyrolysis method to prepare a modified interface layer on the surface of a piston preform; then further densifying the obtained piston perform having the graphene/C interface layer by precursor infiltration pyrolysis, and repeating precursor infiltration pyrolysis until the piston density reaches 1.73-1.78g/cm<3>; and then carrying out graphitization treatment at 2400-2600DEG C for 2-3h, thus obtaining the graphene modified composite piston. The modified carbon matrix composite piston provided by the invention can improve the hot corrosion resistance, room temperature and high temperature tensile strength of piston, decrease the thermal expansion coefficient, and reduce the fuel consumption and harmful substance emission of corresponding engine.