This paper reports the operation of LiB3O5 (LBO) optical parametric oscillator. Regions of its output wavelength are 0.956-1.205μm and 1.488-1.583μm (0.828-0.801μm). Maximum output energy is over 70 mJ/pulse with energy conversion efficiency of 43%. Calculation method and the results of phase-matching curves and effective nonliear coefficients for the biaxial crystal LBO are given in this paper.