We experimentally demonstrated a wavelength-tunable passively mode-locked Erbium-doped figure-eight fiber laser. Wide tunability is achieved using a high-birefringence (hi-bi) fiber Sagnac loop. The filter transmission pass wavelength is controlled by thermally adjusting the hi-bi fiber loop length. The output pulses are wavelength tunable over a range from 1525 nm to 1555 nm. The FWHM of the autocorrelation trace is about 3.1 ps and the pulse spectrum has a FWHM of 1.5 nm. The pulse temporal and spectral widths remain constant over the tunable range.