Doping ZnO into LiNbO3, Zn:LiNbO3 crystal have been grown. The photo damage resistance increases of two magnituder when the ZnO doping concentrations were higher than 6 mol%. This value is similar to that of MgO(>4.6 mol%):LiNbO 3. The frequency doubling conversion efficiency of Zn (6 mol%):LiNbO3 was measured to be about 5%, ligher than that of Mg (6 mol%):LiNbO3. The location of Zn2+ ions and the enhancement machenism of photo damage resistance of Zn:LiNbO3 are discussed in this paper.