Enhancement of sonochemical reaction with the addition of aluminum powder in a sonoreactor is studied. The decolorization reaction between iodine and disodium hydrogenphosphate in a starch solution in the presence of aluminum powder proceeds at a maximum of 2 times faster than that in the absence of aluminum powder. The fast liquid flow is observed due to the reflection at the surface of the aluminum powder, which is in the shape of flakes in the water. The effect of the amount of aluminum powder on the chemical reaction is investigated.