Currently, narrow linewidth fiber lasers with output powers of several kilowatts have been developed; however, their power improvement and system stability are still majorly restricted by stimulated Brillouin scattering (SBS). Based on our previous verification, the tilted fiber Bragg grating (TFBG) can effectively filter the backward-propagating Stokes wave owing to SBS in fibers. This study further verified its suppression effect on SBS through experiments. With an optimized and fabricated TFBG being inserted between a single-mode fiber (SMF) amplifier and a 150-m-length single-mode energy-transmitting fiber, the backward-propagating Stokes wave is strongly rejected with a filtering ratio of approximately 10 dB. Meanwhile, an obvious increasing of the SBS threshold is observed with a value 1.25 times than that in the case without the TFBG, which increases the effective laser output power by approximately 20%. This study provides new insights into the SBS suppression in fibers. Furthermore, it is extremely useful in the further power scaling of high-power narrow bandwidth all-fiber lasers. It also has potential applications in fiber-optic communication and fiber-optic sensing.