Abstract. LiCl was used to improve the surface charge of SiO 2 colloidal spheres prepared by st ber method. And vertical deposition method was used to synthesize the photonic crystal with modified SiO 2 colloidal spheres. The micromorphology, electrical properties and optical properties were characterized by scanning electron microscope (SEM), zeta potential instrument and UV/VIS/NIR spectrophotometer. The surface charge of SiO 2 colloidal spheres can be improved by LiCl solution, and the Zeta potential increases with the increment of LiCl concentration and NH 3 concentration. The position of the transmission dip of the photonic crystals is close to the experimental value.