The invention belongs to the technical field of optical grade polyester films, and particularly relates to a light weather resistant optical grade PET rigid film. The hardening film is prepared from the raw materials of UV curing resin, a photoinitiator, polytetrafluoroethylene, organosilane, montmorillonoid, n-hexadecane, diiodomethane and cyclohexanone, the hardening film adopts UV curing hardening liquid, thus the hardness of the hardening film is large on the basis of the small thickness, the screen protection ability is high, the polytetrafluoroethylene, the organosilane and the montmorillonoid make surface energy of the hardening film low, thus the hardening film is prevented from being deformed by influence of the low temperature, a silicon oxygen bond in the organosilane has long bond length, large bond angle and easy internal rotation, molecules are helical, methyl groups are arranged outwardly and rotated around the silicon oxygen bond, the surface energy is very low, the good hydrophobic and oleophobic properties are achieved, the surface of the hardening film is not prone to being dirty, and the visual effect of a screen is affected to the low extent while the screen isprotected.