Abstract: To meet the requirements for defect-free edge polishing of high-precision fiber optic gyroscope integrated optic modulator LiNbO3 chips, a new polishing process based on pad polishing was developed. According to the analysis on the causes for edge damage during the edge polishing, three solutions were presented:controlling the big particles in polishing material, choosing the low sub-face damage polishing and making the particles size close to or less than double of the critical cutting depth. With the new process, the defect-free edge polishing of LiNbO3 chips could be achieved and the results show that the edges under 1 500 microscope have no visible defect, the chip end face roughness Ra is less than 0.8 nm and the surface flatness reaches better than /2.Additional,this polishing process has great application value.