Abstract: The graphene-oxide-based passively Q-switched erbium-doped fiber laser is first reported. The laser adopts ring cavity configuration, and the Q-switcher is the self-made graphene oxide saturable absorber mirror. Stable Q-switched pulses with the frequency of 68~124 kHz and pulse width of 0.47~1.6 s are output at 80~505 mW incident pump power. Limited by the pump power, the maximum output power is 10 mW, corresponding to the single pulse energy of 80.6 nJ. This kind of new Q-switched fiber laser with graphene oxide as the saturable absorber will have great applications, due to its advantages of low price, simple design and high stability.