In order to explore the reasons why the transmittance of plastic lenses decreases under high humidity and film cracking is prone to occur under high temperature，Ti3O5 and SiO2 are selected as materials with high and low refractive index. TFCalc is used to design and optimize the film system. Electron beam evaporation process is adopted to obtain the antireflection film with an average reflectance R≤1% of 420~880 nm. The test results show that the transmittance of the coated plastic lenses decreased by less than 1% after 24 h at 85 ℃ and 85RH. 2# and 4# lenses show film cracking phenomenon after 24 h at 120 ℃. Changing the baking temperature and increasing the aggregation density of the film layer can effectively improve the waterproof performance and high temperature resistance performance of the plastic lens.