It is reported the experimental study of ultrashort pulse Yb~3+ -doped fiber ring laser. The Yb~3+ -doped fiber is pumped using a 976 nm semiconductor laser. Using the additive pulse mode-locking based on nonlinear polarization evolution, the Yb~3+ -doped fiber laser achieves stable mode-locking by adjusting the orientation of PC. The maximum output power of the laser is 7.02 mW, at the repetition rate of 13.7 MHz corresponding to ~6nm spectrum width.