We reported the experiment result of laser output at 1.57 μm on Nd:YAG 1.06 μm laser using the OPO method and taking the stimulated Brillouin scattering (SBS) backward amplified output as pump source. The maximum output energy was 21.6 mJ, and the corresponding conversion efficiency is 32 percent. Comparaed with the result directly pumped by Nd:YAG 1.06 μm laser, the efficiency is increased by 1.9 times and the threshold is reduced by 1.7 times. The experimental result is in good agreement with the theoretical analysis.