The amplification of the signal of stimulated Brillouin scattering （SBS） is widely used in many area. A method for amplifying the signal of SBS using dual collinear beams in a single optical cell is introduced. The stimulated Brillouin scattering can be induced and amplified in one optical cell. Comparing with previous double-cell technique, the proposed method has the advantages of simple structure and low energy loss. It is necessary for some applications with weak signal of stimulated Brillouin scattering such as lidar for remote sensing, in which double-cell technique is not suitable.