We demonstrate a self-seeded multi-wavelength brillouin-erbium fiber laser with double-brillouin-frequency gap. First, the factor that induces the double frequency gap is inves- tigated. The twice channel gap is induced by the gain difference in different directions. Then, a self-seeded multi-wavelength brillouin-erbium fiber laser with high signal to noise ratio (SNR) is reported. 44 stable output channels (above −25 dBm) with 20 GHz frequency spacing is obtained when the 980 nm pump power is 300 mW.