Abstract: Stimulated Brillouin Scattering (SBS) is a process to product the phase conjugated light. Now it is being pursued as a means for pulse compression, beam combination and wavefront reversal. To achieve a high quality short pulse beam, to select a proper medium is very important. In this paper, the effect of parameters of Brillouin mediums on pulse compression of Stimulated Brillouin Scattering process used as a SBS generator are shown theoretically and experimentally. The theoretical model includes transient process, absorption of medium, and pump depletion. The results show that pulse compression ratio is 8 in 0.68MPa. Dependence of pulse compression on the acoustic lifetime and Brillouin gain coefficients is investigated respectively. The results show that pulse compression versus parame