Manganese oxide minerals are important scavenger of heavy metals and oxidants of changeable valent elements in soils and aquatic environment Previous studies on redox reaction between Mn oxides and Cr (Ⅲ) were mainly achieved by using synthetic Mn oxides, and little literature is available on redox reaction of Cr(Ⅲ) and Mn oxides from soils Fe-Mn nodules were major depositing forms of Mn in soils Influences of pH, ion strength and temperature on the oxidation of Cr(Ⅲ) by Fe-Mn nodules from soils were investi gated by means of chemical analysis and equilibrium techniques The results showed that the amounts of Cr (Ⅲ) oxidized by Fe-Mn nodules increased as pH decreasing, ion strength and temperature increasing It was related to charge properties and electric potential of Mn oxide surface, and coexistence of Fe oxides besides consumption of H⁺ during redox reaction The ranging amounts of Cr(Ⅲ) oxidized by N2-1 and N4-1 contained birnessite and lithiophorite were larger than that by N5-1 contained todorokite and lithio phorite under above conditions These diversities were related to crystallinity, crystal structure, and Mn (Ⅲ) content of Mn oxides in Fe-Mn nodules These data are useful for predicting chrome transport in the environment, and understanding functions of Mn oxide minerals in soil and sediment particles.