In order to reduce the reflectivity of solar cell PET packaging materials, the rigorous coupled wave analysis (RCWA) method is used to optimize the anti-reflection layer based on moth-eye array of PET film. Firstly, the solar light transmission characteristics of conical, parabolic and sinusoidal moth-eye structures are compared. It is shown that the conical moth-eye structure has the best omnidirectional and broadband anti-reflection performance. Meanwhile, effects of geometry parameters on moth-eye array with conical structure are analyzed, which helps to select optimal parameters. On this basis, a moth-eye array based on composite structures composed of cylindrical and conicalstructure is proposed. By optimized geometry parameters, the transmittance of sunlight under large angle incident conditions is further improved. The PET film having moth-eye array with optimized composite structures has a normalized transmittance of 0.9664 for a solar wavelength with a wavelength range of 0.3~1.1μm under the incident angle of 0°~90°, which is 12.77% higher than that without taking countermeasures.