A ring cavity fiber laser was proposed by using graphene as a saturable absorber for fiber optic communication and material processing. The principle how the grapheme could generate pulse trains and the laser output characteristics were studied experimentally. Then the laser induced deposition method was used to transfer the graphene to the fiber end face and place it in the ring laser cavity. By taking a 974 nm semiconductor laser as the pumping source and the Er3+-doped fiber as the gain medium, the laser generated stable pulse trains by changing the orientations of a polarizer above the threshold pump power. The experiment shows that the center wavelength of laser is 1 560.1 nm with a full width at half maximum spectrum of 0.27 nm and the pulse repetition rate is 7.89 MHz with a pulse width of 14.7 ps. It means that the graphene is expected to replace single-walled carbon nanotubes in pulsed laser applications as a novel mode-locked material because of its good saturable absorption properties and a higher damage threshold.