A forward output and a backward output tunable Yb-doped photonic crystal fiber laser (PCFL) with a blazing grating as a tuning element are demonstrated. For the forward output tunable PCFL, when the absorbed pump power is 5.75 W, a tuning range of 59.6 nm from 1050.6～1110.2 nm is obtained. The 3 dB bandwidth is around 0.1 nm. Side-mode extinction is more than 44 dB. A maximum output power of 677 mW is obtained with a slope efficiency of 14% for a tuning wavelength of 1085 nm. Over the whole tuning range, the variety of output power is less than ±0.34 dB. For the backward output configuration, it is tunable over 50.9 nm when the absorbed pump power is 4.43 W. For all tuning wavelengths, the 3 dB bandwidth is less than 0.08 nm, side-mode extinction is better than 50 dB. When the tuning wavelength is 1075 nm, a maximum output power of 2.21 W is obtained with a slope efficiency of 73%. For the two configurations tunable PCFL, output of both two lasers are linearly polarized and the polarization extinction ratio is more than 89.5％. The effect of re-absorption in ytterbium doped active fiber on the tuning range is also discussed.