To provide a support system for adjusting control parameters for ozone injection, which supports the adjustment of control parameters suitably when it is necessary to change control parameters for ozone injection due to fluctuations of the water quality at an intake source of a water purification plant.

The support system for adjusting control parameters for ozone injection is provided with: an ozone reaction processing simulator 2 for simulating an ozone reaction process by using a theoretical model on the basis of water quality data and set condition data; an ozone injection control simulator 5 for simulating ozone injection control on the basis of the result simulated by the ozone reaction processing simulator; and a control parameter output part 13 for outputting proper control parameters for ozone injection, which are used for injecting ozone into an actual plant, on the basis of the result simulated by the ozone injection control simulator.