Graphene-based passively mode-locked erbium doped fiber laser is presented. Multilayer graphene was obtained by mechanical exfoliation of pure graphitic block and deposited on the fiber ferrule. The mode-locking performance was investigated under various laser pumping conditions. The laser could operate at fundamental repetition rate of 16.34MHz with 844fs pulse duration and 30mW average output power. Also harmonic-mode locking of the laser is demonstrated. 294 and 800MHz repetition rates were obtained (corresponding to the 18th and 49th harmonic of the fundamental repetition frequency, respectively) with nearly transform-limited pulses.