The utility model discloses a plastics expansion nail, including the expansion nail body and with expansion nail body matched with cock body, the cock body includes that the nose circle head reaches and nose circle head integrated into one piece's the portion that stretches into, the expansion nail body includes that circular chassis reaches and circular chassis integrated into one piece's plasmodium, opens on the circular chassis to have to supply to stretch into a male through -hole, the portion of stretching into inserts through -hole and the cooperation of plasmodium joint. The utility model discloses the compressed warp behind the toper variant part pressurized of expansion nail body front end, the power back retrieval original shape that disappears, and the cock body uses with the cooperation of expansion nail body, in the cock body inserts the direction through -hole, the tight expansion nail body of expansible to prevent that the expansion nail body from coming off from outer gadget. This plastics expansion nail is light in weight not only, and intensity is high in addition, and the assembly precision between other automobile parts is high, the good reliability, and assembles simple and conveniently, practices thrift man -hour.