Abstract: In order to improve the light transmittance and solve the Fresnel reflection problem which is common in optical systems, we designed a two-dimensional rectangular SiO2 photonic crystal surface grating structure. Using the Legendre polynomial expansion method to calculate the transmittance in the visiblenear infrared wavelength range of the incident light wave of the structure, we found the appropriate duty cycle e, the grating depth h, and the substrate thickness d, which could stabilize the change of transmission rate and make the average rate reach over 96% when the incident angle varied in the range of 0～60 and the incident wave length in the range of 400 nm～1200 nm.