The recent progress of HfO2 and ZrO2 doped LiNbO3 crystals was reviewed. LN:Hf crystal has similar optical damage resistance to LN:Mg, but LN:Zr has much better property than LN:Mg. LN:Fe,Hf and LN:Fe,Hf crystals have both fast photorefractive response speed and high saturation diffraction efficiency. And the distribution coefficient of ZrO2 in LiNbO3 is close to one. These results indicate that the tetravalent ions doped LiNbO3 will be the excellent nonlinear optical crystals.