Abstract: Reactive Oxygen Species（ROS）solution，which was produced through strong ionization discharging plasma，was used to kill Bacillus subtilis varniger. ROS solution was sprayed to cope with biological pollution. Several operation parameters, such as PH value, solution temperature, spraying time and effect time, were studied. The effects of operating conditions on the killing rate of Bacillus subtilis var.niger were analyzed The results show that the treatment efficiency of Bacillus subtilis var.niger in alkaline solution is higher than that in acid solution. The killing rate of Bacillus subtilis var.niger increases with the decrease of the temperature and the increase of the spraying time and effect time., and the order of strength of the affecting factors is effect time>spraying time>pH value>solution temperature.