Two-layer antireflective films were prepared on Na-Mg-Ca-Si glass substrate by sol-gel process starting from metal alkoxides: Si(OC2H5)4, Ti(OC4H9)4. The transmittance of glass was increased obviously (>95%), the reflective index was reduced to 1.95 through visible light range. TEM observation showed that SiO2 film is compactly joined to TiO2 film and TiO2 film to the substrate. TEM-EDX analysis of the films, film-substrate interface and substrate revealed that with the increase of Ti content, the content of Mg，Ca and Si decreases, however, the content of Na increases. The diffuse of Na+ from the substrate to the film is negative diffusion.