With the rapid development of photovoltaic industry in recent years, anti-reflective glass comes into researchers’ sight. This article uses two-step chemical etching method to prepare Na2O-CaO-SiO2 flat glass with anti-reflective properties. The transmittance， surface morphology， cross-section film thickness， surface chemical composition， acid resistance and hardness of samples were measured by spectrophotometer， scanning electron microscope， atomic force microscope and X-ray energy spectrometer. The relationship between reaction temperature， reaction time， glass film structure and transmittance were studied. The Si—O bonds on Na2O-CaO-SiO2 flat glass surface were broken by etching glass surface with weakly alkaline mixed salt solution, and a nano film structure is formed on the surface of glass. When the corrosion reaches a certain thickness, destructive interference of a certain wavelength of light occurs on glass surface, with a maximum transmittance of 97.8%. The glass composition remains basically unchanged before and after etching, and the pencil hardness reaches 3H.