An erbium-doped fiber laser(EDFL) ba sed on a passive feedback fiber ring(FFR) and saturable absorber (SA) has bee n proposed,which effectively supports dual-wavelength single-longitudinal-mode (SLM) laser operation.The polarization-maintaining f iber Bragg grating(PM-FBG) is used as the wavelength selection device to pro d uce dual-wavelength.Two 30∶70optical couplers and a 1m unpumped erbium-doped fiber are selected to make up the pas sive feedback fiber ring by calculation and simulation,which is used to increase the interval of mo des and steady the laser operation.The 3m unpumped erbium-doped fiber forms a passive self-tracking f ilter to ensure a stable single-longitudinal-mode fiber laser operation together with the passive feed back fiber ring.At room temperature,under 400mW pump power,dual-wavelength single-longitudinal-mode laser is achieved, the 3dB line widths are both less than 0.02nm,the centre wavelengths are separ ately 1545.45nm and 1545.90nm,the peak power values are separately 8.158dBm and 8.898dBm,and the optical signal-to-noise ratio (OSNR) of output is about 60dB.Within 3hours,the maximum fluctuation of each peak power is less than 0.45dB,which shows that the proposed fiber laser is quite stable.Mor eover,by adjusting the polarization controller,the maximum peak power values of single-wavelength are up to 13.941dBm and 15.432dBm.