The invention relates to a protective film. The protective film comprises a film protecting layer, a first adhesive layer, a first hardening layer, a first softening layer, a main film layer, a second softening layer, a second hardening layer, a second adhesive layer and a peeling layer which are sequentially stacked, wherein the first hardening layer and the second hardening layer are of a mixture of urethane acrylate, epoxy acrylate and polyester acrylate which are mixed according to the mass ratio of 6:(1-3):(1-3); and the first softening layer and the second adhesive layer are of a mixture of the urethane acrylate, the epoxy acrylate, the polyester acrylate and an antistatic agent which are mixed according to the mass ratio of (3-6):(1-4):(1-4); and the main film layer is made of polyethylene glycol terephthalate. The protective film has a high hardness. In addition, the invention further provides a preparation method of the protective film.