Iron oxides in soils play very important roles as one of the acceptors of electrons transferred from reducing organic matters under submergence condit ion.Attempt had been made to simulate the reaction between reducing organic matters and iron oxides in soils in the study, in which vitamin C was used as the reducing organic matter and goethite synthesized in laboratory was also used.The result indicated that an increase in pH was observed in the process of reaction between vitamin C and goethite, due to the proton consumptions.It was suggested that the reaction between vitamin C and goethite was heterogeneous reaction and, it took rather longer time to reach an equilibrium.At the beginning of reaction, the change of Fe²⁺ in solution could not be observed, suggesting that the dissolution of Fe²⁺ from goethite was very slow.pH had effect on the reaction, the reaction rate decreased with an increase in pH.The reason for this phenomenon might be inferred from influence of pH on the amount of posit ive charges on the surface of goethite.