The advantages of using NOLM as saturable absorber to compress pulse in mode-locked fiber lasers are analyzed theoretically. Experimentally the NOLM is placed in an actively mode-loked erbium-doped fibre ring laser to form a figure-eight actively and passively mode-locked fibre laser. 12 ps mode-locked pulses centered at 1.543 μm were obtained at the modulation frequency of 2.498749 GHz, with time-bandwidth product of 0.33. 3.715 mW output power is achieved with 50 mW pump power. Meanwhile, 2～4 rational harmonic(RH) mode-locked pulses with uniform amplitude were obtained at the modulation frequency of 2.499344 GHz, 2.499114 GHz, and 2.498999 GHz respectively.