The large aperture optical switch used in the high-power laser driver for inertial confinement fusion adopts the plasma electrode Pockel cell. Being different with the regular plasma electrode electrooptical switch, the one-pulse-process (OPP) driving electrooptical switch is driven only through the positive and negative switching pulses with relatively high voltage, without isolated large current plasma generator. The design of the OPP electrooptical switch is described, and the experimental setup of the electrooptical switch with 280 mm×280 mm aperture is established. The testing results of the electrooptical switch with CW laser show the switch efficiency of this electrooptical switch is 99.3%, and the switch rising time is 90 ns.