The two_cell stimulated Brillouin scattering (SBS) system that uses different media in generator and amplifier cells is investigated. It is demonstrated that th e seed light still has enough amplification when the Brillouin frequency shifts of this two media are near and their Brillouin line_widths are crossed. In exper iment, when CCl4 is used as an amplifying medium and liquid mixture of CCl4/ CS2 as generating medium, and the two_cell SBS system is pumped by Nd:YAG Qs witched laser, the influence of the deviation of Brillouin frequency shift on seed light Brillouin amplification is studied. The result shows that amplification efficiency and pulse compression ratio are still large enough when Brillouin frequency deviation is small. Moreover, under the condition of CS2 as the amplifying medium and benzene as the generating medium, seed light amplification efficiency of 44, pulse compression ratio of 72, phase_conjugation fidelity of 98%, and stability of seed light amplification efficiency of <3% are obtaine d.