A new type of heavy metal chelating agent，potassium diisopropyl dithiophosphate was synthesized and the treatment of sediment contaminated by heavy metals by this chelator was investigated.The results indicated that when the dosage of potassium diisopropyl dithiophosphate was 3%(mass)

the stabilization rate of heavy metals in sediment

such as Pb

Cu

Cd

could reach more than 85%

and the effect was better than inorganic stabilization chemicals

like Na2S and Na3PO4. After treatment the sediment could meet the US standards for heavy metals waste  landfill.Meanwhile

the maximum leaching capacity of the treated sediment was much lower than the case with inorganic stabilization chemicals

and such stabilization effect could be obtained in a wide range of pH. The heavy metals in sediment after treatment could be transformed from exchangeable to organically bound and residue

reducing secondary contamination risk when the environment has changed.