The invention discloses a high-power optical fiber laser. The laser structurally comprises a residual light collector, a red light / signal light beam combiner, a red light laser, a reverse cladding light mode stripper, a forward pumping pump source module, a forward pumping / signal beam combiner, a high-reflection grating, doped optical fiber, a low-reflection output grating, a reverse pumping / signal beam combiner, a reverse pumping pump source module, a forward cladding light stripper, and output optical fiber with an antireflection film end cap. Based on a linear fabry-perot resonance cavity structure, the forward pumping pump source module and the reverse pumping pump source module, with different wavelengths, provided with narrow-band protection filters are adopted, the forward pumping / signal beam combiner and the reverse pumping / signal beam combiner pump doped optical fiber from the front end and the back end of the doped optical fiber through the high-reflection grating and the low-reflection output grating at the same time, so that multi-kilowatt-class power stable output of the optical fiber laser is achieved, and mutual damage of residual pumping light on two sides to a pumpsource chip is avoided.