The 514 nm visible laser-induced preferential domain nucleation effect is investigated in the 3% mole fraction hafnium-doped lithium niobate crystal.The local variation of phase distribution during the laser-induced preferential domain nucleation is in-situ recorded and is reconstructed by the digital holographic interferometry.The nucleation field decreases exponentially with increase of irradiation intensity.The space-charge field along Z direction has an important influence on the laser-induced preferential domain nucleation.According to the experimental results,a qualitative model for the laser-induced preferential domain nucleation process in lithium niobate crystal is presented.This model not only provides the essential information for the future optimization of laser-induced domain engineering,but also supplies the new experimental evidences for the future mechanism investigation of laser-induced domain nucleation in LiNbO3.