Abstract: In order to achieve high peak power and narrow pulse-width semiconductor laser, a driving system for the laser was designed. The electrical circuit for producing narrow-high current pulses based on MOSFET as a fast switch for the discharge circuit was analyzed. The working procedure of the MOSFET as a fast switch was discussed. In order to make the MOSFET switch as fast as possible, the push-pull driving circuit was brought forward and the circuit of narrow trigger pulses was designed. When the LD was connected to the RC discharge circuit, the peak power of the emission laser could be up to 67.5W and the full width at half maximum (FWHM) could reach 20ns. Finally, the impact factors on the pulse width of the laser were analyzed.