Abstract In this paper, a multi-wavelength fiber laser based on self-seed light amplification and wavelength-dependent gain is proposed and demonstrated. A pumped erbium-doped fiber (EDF) in the linear cavity acts as the seed light source, which is also conducive to the gain equalization. A high power erbium-doped fiber amplifier (EDFA) is deployed for self-seed amplification, and a highly nonlinear fiber (HNLF) is incorporated in the ring cavity to alleviate the mode competition induced by the homogeneous gain broadening of EDF. In the experiments, 25-wavelength operation within 0.5 dB uniformity is achieved with the extinction ratio of ~42 dB using 500 m HNLF, and 38-wavelength operation within 3 dB uniformity is obtained with the extinction ratio of ~35 dB using 1000 m HNLF. Our proposed laser has more lasing wavelengths with a better uniformity and stability.