Abstract: A mathematical model of laser compensation propagation process by combining the stimulated Brillouinscattering (SBS) and laser propagation in the atmosphere is constructed and the numerical simulation is also conducted. On the basis of realizing a beacon of a small area on an uncooperative and extensive target with SBS threshold, we presented and demonstrated the feasibility of the method to actively obtain the phaseconjugatelight on the target. The experiments of laser propagation with SBS are conducted in case of a 250m distance, which shows that by utilizing the SBS threshold effect the small area beacon could be obtained on the target actively.