A wavelength tunable mode-locked fiber ring laser is described, in which a chirped fiber Bragg grating (CFBG) is included to give a large dispersion in the cavity. By tuning the modulating frequency, the wavelength of pulse laser is tuned. The tuning range is about 2 nm, limited by the spectral band of CFBG. The pulses with positive chirp are obtained. The frequency of pulse is 2.5 GHz and pulse width is about 60 ps.