A lot of electrical equipments using electrical discharges have been put into practical use. RecentIy，a method to produce discharge plasmas by pulsed power has been proposed for the discharge chemicl treatments. A pulsed power generator with nanosecond pulse width was developed as an electrical source equipment for the discharge chemical treatments. The pulsed power generator mainly consists of a tesla transformer and a highly pressurized gas gap switch. When the charging voltage is 2.7kV，the peak output voltage is about 40kV and the pulse width(FWHM)is approximately l.5ns. To evaluate practical performance of the pulsed power generator developed，the experiment of ozone production was attempted. The maximum ozane concentration of 17g/Nm3 and the maximum ozone yield of 60g/kWh are approximately obtained in the experiment.