Abstract: The working principle of the plasma underwater ozone generator is expatiated, the differential equations of the circuit is established , the effects of the main electrical parameters of the circuit on the high-voltage pulse discharge voltage amplitude are studied. Then the electrical circuit of underwater ozone generator is simulated by Matlab/Simulink. According to the simulation results ,determines the electrical circuit parameters, then underwater ozone generator is designed and manufactured to carry on experiment research. Simulation and experiment results show that: selecting appropriate parameters and power frequency can generate high voltage that close to or more than twice the amplitude of the supply voltage on the capacitor C2; it provides a theoretical foundation for parameters selection of underwater ozone generator.