The paper took sediment from city river as the target and used EDTA washing to study the decontamination of sediment.It probed the influence of the factors such as EDTA concentration, washing time and liquid/solid ratio on washing efficiency for the purpose of providing parameters for real application.The result indicated that washing conditions such as EDTA concentration, washing time and liquid/solid ratio all have significant impact on washing effect.EDTA of 0.1 mol/L, liquid/solid ratio of 10:1 can achieve the best result.70%-80% of Cu and Cd could be removed after 30 min of washing. In addition,the form distribution of heavy metal in sediment before and after washing was compared. It investigated the combination way of sediment and heavy metal to affect washing efficiency.Washing by EDTA was more effective to heavy metal in exchangeable and carbonate-bound forms while relatively ineffective to Fe-Mn oxides, organics-bound species and residuals. Therefore, it is advisable to conduct the form analysis of heavy metal so as to decide whether EDTA is used for washing.