Abstract: An experiment was carried out to kill Microcystis aeruginosa in water with strong ionization discharge,and killing rate of Microcystis aeruginosa in relation to aeration rate,initial population of the bacteria,duration of incubation,pH and temperature was studied.It was found that within a certain range,the killing rate increased with rising aeration rate,initial population of the bacteria,duration of incubation,pH and temperature.When the aeration rate was set at 500 mL·min^-1,initial population of the bacteria at 9×10⁶ mL^-1,pH at 9.18,temperature at 317 K,duration of incubation at 4 days,and duration of treatment at 10 minutes,the killing rate of Microcystis aeruginosa reached as high as close to 100.0%.