Absorption characteristic of lithium niobate crystals doped with chromium and copper (Cr and Cu) has been investigated. It is found that there are two apparent absorption bands for LiNbO₃ : Cr : Cucrystal doped with 0.14 wt. % Cr₂ O₃ and 0.O11 wt.% CuO;one is around 480 nm,and the other is around 660 nm. With the decrease of doping composition of Cr and the iN_cr ease of doping composition of Cu,there doesn't exist an apparent absorption band in the shorter wavelength range. The higher the doping level of Cr,the larger the absorbance around 660 nm. Though 633 nm red light locates in the absorption band around 660 nm,the absorption at 633 nm will not help the photorefractive process. For LiNbO₃ : Cr : Cucrystals,by changing the recording light from 633 nm red light to 514 nm green light,sensitizing with 390 nm ultraviolet light and 488 nm blue light respectively,nonvolatile holographic recording can be realized.Doping appropriate Cr (for instance: N_cr= 2.795X10²⁵ m^－3 and N_cr/N_cr=1) benefits to the improvement of holographic recording properties.