The invention discloses an optical thin film with double hardening layers and a preparation method thereof. The optical thin film comprises a transparent substrate and hardening layers coated on upper and lower surfaces of the transparent substrate, wherein pits are formed on the surface of one hardening layer; and the ratio of the sum of the areas occupied by the pits to the area of the hardening layer is 2:100-99:100. Due to the pits formed on the surface of the hardening layer, the effect of the optical thin film added with particles is achieved, the friction coefficient is reduced, the surface smoothness of the thin film is improved, the problem of flaws on the surface of the thin film caused by particle aggregation is solved, the high light transmittance of the thin film is simultaneously kept, and the optical thin film can be widely applied in the field of touch screens. The method is simple in process, low in cost and environment-friendly.