In this paper, we experimentally demonstrate a novel wave-length tunable and frequency spacing switchable MBEFL by utilizing optical gain and absorption during the SBS process. The frequency spacing of the laser can be easily switched between 10 GHz and 20 GHz by just changing the Brillouin pump(BP) power. Compared with [16], the generation of doubled frequency spacing in our proposed scheme is not based on the discrimination of the even-order and odd-order Stokes waves. The influences of pump powers,BP wavelength, and fiber length on the performance of the proposed MBEFL are investigated experimentally.