A master oscillator power amplifier (ΜΟΡΑ) system was designed, SBS phase-conjugate mirror was used in the system, the seeder was a narrow-linewidth laser of twisted mode with Cr4+:YAG as passive Q-Switch, two amplifiers were used to pass twice, image-relay telescope and 900 rotator was used to compensate the depolarization bewteen amplifiers, three liquids of CCl4. FYeonll2 and CS2 were used in phase-conjugate mirror, SBS reflective rate and SBS fidelity were measured.