The rectangular airlift sonoreactor combined with sparging ozone was developed. Tetraphenyl porphine tetrasulfonic acid was used as a sample to be decomposed and the decomposition performance was experimentally studied. First, by using only ultrasound, the superficial gas velocity and the riser width were changed, and the decomposition conversion and the flow characteristics were examined. It was found that the decomposition conversion became higher with increasing liquid velocity above the ultrasonic oscillator because the sample was more effectively supplied to the ultrasonic reaction field. Next, the decomposition experiment was conducted by using both the ultrasound and ozone. It was confirmed that the decomposition performance was enhanced by the combination with sparging ozone.