A tunable multi-wavelength random fiber laser, with single-mode fiber and ring structure forming halfopen cavity, has been proposed. Tunable Brillouin pump laser is used to achieve tunable random lasing. The results show that the proposed laser has random lasing with four wavelengths, which can be accurately controlled by the output power of erbium-doped fiber amplifier when Brillouin pump wavelength is 1550.01 nm. The threshold power of the proposed laser from the first Stokes line to the fourth Stokes line are 12, 31.6, 73 and 610 mW, respectively. The slope efficiency of the first stokes wave is 12.5%. For fixed output power of erbium-doped fiber amplifier of 631 mW, the output power of the proposed laser decreases exponentially with lengths of optical fibers as random distributed feedback media. The output wavelength of the random fiber laser can be tuned between 1528 nm and 1580 nm. The scheme of half-open cavity can effectively avoid the peak power difference of odd-order and evenorder Stokes lines.