A stable continuous-wave dual-wavelength Yb3+-doped fiber laser is demonstrated, in which the resonance cavity is composed of a fiber Bragg grating fabricated in a polarization maintaining fiber (PM-FBG) and a high reflectivity dichromatic mirror. The laser achieves output power of 1.0 W, signal to noise radio (SNR) of 48 dB, slope efficiency of 34%, as well as a very narrow linewidth of 0.2 nm. The dual-wavelength laser′s tuning range is 8 nm by stretching and compressing the PM-FBG which is glued on an arch elastic beam. The polarization characteristics of the laser are then verified by measuring the laser power transmitted through a Glan-Thomson polarizer.