A pot experiment was conducted with different DDT concentration,i.e.0,0.5,5.0 mg kg^-1 respectively,to study residue dynamics of DDT and its main metabolites in paddy soils with and without ryegrass growing.The total growth period was 81 days.The results indicated that the residue of DDTs decreased steadily with the time and at a greater rate in the earlier stage.Compared to the soils without ryegrass growing,DDTs in the soils under ryegrass growing decreased by 27.26% and 20.50% respectively by the end of the experiment,for the 0.5 and 5.0 mg kg^-1 treatments,and significant differences in p,p DDT residue were observed on the 16th,32th,64th and 81th day.It could be contributed to the release of enzyme and other organic secretions from plant root systems,which could effectively stimulate degradation of DDT.Additionally,DDE in creased gradually along with the time.