Abstract: | The pure congruent LiNbO3, Er:LiNbO3 and Zn,Er co‐doped Li‐rich LiNbO3 crystals were grown by Czochralski method. The X‐ray diffraction method and ultraviolet‐visible absorption spectra of the crystals were used to analyze the structure of the crystals. The photo‐damage ability resistance of the crystals was measured. The Zn,Er co‐doped Li‐rich LiNbO3 crystals show a decrease in lattice constant values, a shift in absorption edge of ultraviolet‐visible absorption spectra towards shorter wavelength, and three orders of magnitude increase in photo‐damage resistance compared to congruent LiNbO3 crystal. The intrinsic and extrinsic defects are discussed to explain the enhance of the photo‐damage ability resistance |