A new dual-wavelength erbium-doped fiber ring laser is proposed. By using multi-filtering method to select working frenquencies or modes ,the mode hopping between the neighboring modes can be effectively suppressed. Simultaneity by using the polarization hole burning effect, incorporating with the contrary propagation of the two light beams, the inhomogeneous broadening is significantly increased in the gain medium, and thus a stable dual-wavelength Er-doped fiber ring laser operating in single-longitudinal mode and single-frequency was demonstrated. Wavelength spacing between the two wavelengths was tunable from 0.019 nm to 15 nm. By suitable adjusting the tunable fiber filter, its intensity was of 25 dB over the noise and only one beat tone at 472.5 MHz was found in the spectral rang from 100 Hz to 3 GHz.