The LiNbO3 crystals doped with Cr3+ ion (Cr:LN) and co-doped with Cr3+ and Zn ions (Zn:Cr:LN) were grown by the Bridgman method. The absorption coefficient and concentration of Cr3+ in crystals were measured by UV/Visible spectra and inductively coupled plasma (ICP) spectrometry, respectively. The effective distribution coefficients (k) of Cr3+ in the crystals were calculated. The results indicated that the k for Cr:LN crystal decreased from 3.75 to 2.49 as the incorporating concentration of Cr3+ increased from 0.1 to 0.5 mol%; the introduction of ZnO in Cr:LN induced the reduction of k value effectively. However, the k value increased from 1.85 to 2.25 as the incorporating concentration of ZnO increased from 3 to 6 mol%. The variation of the k value was explained by the suppressing effect of ZnO on the incorporation of Cr3+ ions and the distribution of Cr3+ in LN.