A tunable multi-wavelength Brillouin fiber laser with double Brillouin frequency spacing based on ring cavity is demonstrated.The Brillouin fiber laser consists of a 3 dB-coupler,a tunable laser(TLS),a 980 nm pump laser diode,and a ring cavity to generate double-Brillouin frequency spacing.The multi-wavelength optical signal with about 20 GHz or 0.16 nm frequency spacing is achieved by removing the even-order Stokes lines.The effects of BP optical power and 980 nm pump power on the number of Stokes are studied.The power of 980 nm pump laser and BP are fixed at 26 dBm (400 mW)and 10 dBm,11 stable output channels with 0.16 nm spacing and the tuning range from 1530 nm to 1566nm are obtained.