The photodegradation of gamma-666 on surface soils with low amount of organic substance was studied. The results showed that photodegradation rate of gamma-666 was fitted for pseudo one-order kinetics. The constants of photodegradation rates increased from 0.0052 h-1 to 0.0340 h-1 with the increase of Fe2O3 contents between 0.40% and 5.40% in soils. These results showed that Fe2O3 in soils with low amount of organic substance had remarkable catalysis on photodegradation of gamma-666.