Gain-switched semiconductor lasers tend to produce optical pulses that are wide in width and have a pulse base of a certain size. In order to obtain pulse quality of gain-switched semiconductor lasers, a three-stage pulse shaping scheme was proposed. First, the optical pulse width at the output of the gain-switched semiconductor laser was compressed from 39.381 to 26.681ps using a dispersion-compensated fiber. Then, the width of the optical pulse was further compressed by using an erbium-doped fiber amplifier and the high-order soliton effect of a dispersion shifted fiber to 20.916ps. Finally, the self-phase modulation effect of the semiconductor optical amplifier was used to distinguish the spectrum of the pulse pedestal from the pulse center, and the optical filter was used to filter out the part of the spectrum corresponding to the pulse pedestal, thus eliminating the pulse pedestal and compressing the pulse width to 18.497ps. The experimental results show that this three-stage pulse shaping scheme can effectively compress the pulse width and reduce the pulse pedestal, thus improving the quality of the output optical pulse of the gain-switched semiconductor laser.