Abstract: Mg:Sc:Fe:LiNbO₃ crystals were grown by Czochralski method from various ratios of Li/Nb= 0.94,1.05,1.20 and 1.38 in melt.The IR spectra were measured in order to investigate their defect structures,the OH^-absorption peak of the crystals with Li/Nb=1.05 was 3466cm^-1,3481cm^-1, 3504cm^-1,while the OH^-absorption peak of the crystals with Li/Nb=1.38 was 3504cm^-1, 3535 cm^-1.The results indicated that the Sc concentration reaches the threshold priority.The optical damage resistance was characterized by the transmitted beam pattern distortion method.The threshold intensity of the crystals with Li/Nb=1.05 is 2.0×10⁴W/cm²,three orders of magnitude higher than that of Fe:LiNbO₃.The photorefractive properties of Mg:Sc:Fe:LiNbO₃ crystals were measured with He-Ne laser at the wavelength of 632.8nm by two wave coupling method.As the Li/Nb ratio increased,the diffraction efficiency and dynamic range of crystals decrease,the write time and the erasure time decrease, and the photorefractive sensitivity increase.It has been found that,the optimal Li/Nb ratios is 1.05 among this crystal series.The effect of Li/Nb ratios on the holographic storage properties of Mg:Sc:Fe: LiNbO₃ crystals is discussed.