The main problems of classical angle-tuning and temperature-control tuning in optical parametric oscillator are the complexity of operation and slowness of tuning rate. However, electrooptic tuning takes advantage over in operation and rates. Based on the electrooptical effect of the nonlinear optic crystal LiNbO3, pumped by 1.064 μm Nd∶YAG laser, when the cut angle θ=47.5°, DC voltage varying in the range of -4.5～4.5 kV is applied to LiNbO3 and tunable output of optical parametric oscillator is obtained. The maximum output energy is ～2.6 mJ and the conversion efficiency η is ～17.3%. The experimental results agree well with the theoretical calculation. This is a viable novel approach for changing the optical parametric wavelength.