Stimulated Brillouin scattering (SBS) is a nonlinear scattering process that involves the interaction of laser light and acoustic waves in a medium. SBS can limit the laser power and efficiency in various applications, such as inertial confinement fusion, optical fiber communication, and narrow-linewidth fiber laser. In this paper, we investigate the suppression of SBS by seeding an ion acoustic wave (IAW) in a two-color laser system, where two laser beams with different frequencies and polarizations are combined to form a composite beam. We explore the mechanism of using one of the laser beams to generate an IAW via SBS, which acts as a seed for the harmonic generation and ion acoustic wave decay of another IAW, and then affects the SBS of the other laser beam.