Based on gain homogeneity technology, a new type of dual-wavelength fiber laser is proposed and demonstrated. Linear cavity structure is used in the fiber laser, two Er³⁺-doped superimposed fiber gratings with reflectivity above 99% are used for wavelength selection, and Er³⁺-doped fiber is used as the gain medium. The experimental results show that precise adjustment of the mechanical stress at two ends of the superimposed fiber gratings can regulate the reflectivity (or transmissivity) of cavity lenses at the output end at wavelengths of λ₁ and λ₂, i.e. regulate the laser loss, which makes the gain and loss at two wavelengths in the resonance cavity match well, inhibits mode competition in the resonance cavity, and achieves stable simultaneous dual-wavelength laser emission with wavelength interval of 0.932 nm. The threshold power of the proposed laser is 4 mW, the 3 dB band width is 0.02 nm, the 30 dB band width is less than 0.2 nm, and the side mode suppression ratio is 51.96 dB. This laser have such advantages as simple structure, stable output at room temperature, narrow band width and low threshold.