The invention relates to the field of optical fiber lasers, in particular to a C+L band multi-wavelength optical fiber laser with one-way feedback, which comprises an optical fiber annular chamber, a high birefringence optical fiber annular mirror and an one-way feedback mirror, wherein the optical fiber annular chamber comprises a first semiconductor optical amplifier, a second semiconductor optical amplifier, an optical fiber annular chamber coupler, a first optical isolator, a second optical isolator, a first optical fiber polarization controller, a second optical fiber polarization controller and a circulator; the high birefringence optical fiber annular mirror comprises a 3dB coupler, a high birefringence optical fiber and a third optical fiber polarization controller; and the one-way feedback mirror is formed by sequentially connecting a fourth optical fiber polarization controller, an output coupler and a Faraday feedback mirror. The optical fiber laser of the invention can obtain multi-wavelength stable output in the C+L band at room temperature, the wavelength interval meets the WDM ITU (Wavelength Division Multiplex International Telecommunication Union) standard of 100GHz and can be integrally adjusted continuously in the range of 50GHZ, the line width of the output wavelength of the laser is less than 0.1nm, the output power of each channel is uniform, the power difference between every two wavelengths is less than 6dB, and the signal-to-noise ratio is greater than 25dB.