This application provides a self-seeding fiber laser, including: an arrayed waveguide grating; a gain medium, coupled to one branch port of the arrayed waveguide grating; a Faraday rotator mirror, coupled to a common port of the arrayed waveguide grating, and configured to reflect a part of optical signals transmitted by the gain medium and form injection light returning to the gain medium; where the gain medium, the arrayed waveguide grating, and the Faraday rotator mirror form a laser resonator, and the arrayed waveguide grating is configured to perform wavelength selection in the laser resonator; and a compensation apparatus, coupled to the gain medium and configured to provide a compensation current for the gain medium selectively according to power of the injection light.