2, 4-dichlorophenoxyacetic acid（2, 4-D） is a herbicide widely used in the world.The compound persists under most environmental conditions, yet it is rapidly transformed under certain anaerobic conditions.A experiment was conducted to determine the degradation of 2, 4-D and CO2 evolution in brown earth and chernozems.2, 4-D was added to each soil at rates of 1mg/kg of soil.After 55 days of incubation, degradation of the 2, 4-D was measured.The results showed that extent of mineralization was about 70-80%, with no significant differences between the two soils.Degradation of 2, 4-D was difference under aerobic condition as compared to anaerobic conditions for two soils.Under aerobic conditions, all of 2, 4-D was degraded in brown earth and chernozem in approximately 45d and 50d respectively.While under anaerobic conditions, the degradation needed 50-60d.