A tunable L-band erbium-doped fiber ring laser whose wavelength selection mechanism is formed by the combination of a polarization controller and a polarizer is demonstrated. The output wavelength can be tuned in a wide range of 41nm , from 1569nm to 1610nm , by changing the states of the polarization controller in the cavity. A narrow linewidth can be obtained by introducing a high birefringent PMfibre in the cavity , linewidth in 3dB≤0. 12nm. A high slope efficiency of 24. 7 % is obtained at lasing wavelength of 1590nm. The relationship between the output coupling ratio, output power and tunable range is also investigated.