Pulsed high-voltage discharge in water whose application has been payed wide attention is a new advanced oxidation water treatment technology.This work investigated the inactivation of Chlorella in the same parameters with liquid discharge system of a needle-plate and a plate-hole-plate reactor,and compared the killing rates of algae and input energies of these two reactors.The result shows that the killing rate increased significantly when the voltage increases.The killing rate of algae arrived 100%when the discharge voltage is 28kV in plate-hole-plate reactor and 26kV in needle-plate reactor.The discharge current,instantaneous power and single pulse input energy are related to algae killing rate intensely.