Making use of optical phase conjugation effect and Q-switch effect in stimulated Brillioun scattering (SBS), a Nd:YAG laser with phase-conjugate resonator is developed. By this way, the reflecting mirror and Q-switch in traditional lasers are not used. The laser output is 100 mJ, and the pulse width is 13 ns. The corresponding total converse efficiency of the laser is 0.47%. In addition, a KTP optical parametric oscillator was inserted into the phase-conjugate resonator, the optical parameter oscillator (OPO) output wavelength of 1.57μm and the output energy of 15mJ can been obtained. The result indicates that the OPO in SBS phase conjugation resonator is feasible.