A passively Q-switched mode-locked fiber laser based on graphene saturable absorber mirror is reported. A large-mode-area double-cladding Yb-doped photonic crystal fiber is adopted as a gain medium and a linear cavity is used. At pump power of 12 W, the maximum output power of 115 mW is obtained and the spectrum is centered at 1039 nm with full width of half maximum of 6 nm. The experimental results and the phenomenon are discussed and analyzed.