Abstract: Autogenic pollution sources coming from lake sediment motion process aggravate ecological environment deterioration of lakes. A study of settlement law of lake sediment after suspension by the action of water wave provides a reference for understanding causes of water quality change and ecological environment governance of lakes. Settlement experiments of sediment from the Taihu Lake, Longgan Lake and Caohu Lake under hydrostatic conditions were performed in an organic glass cylinder. The changes in sediment concentrations under the conditions of different initial sediment concentrations and different water depths have been studied, and the laws of the sediment settlement of three lakes have been analyzed, which can approximately represent the dynamic state of the lakes sediment. The analysis results show that the settlement of sediment from three lakes is charactorized by the flocculating settling, and that the settlement process and velocities have quantitative changes and fundamental changes comparing with a single particle sediment. The average flocculating settling velocities increase with the increment of settling height and sediment concentration. The flocculating settling velocities of the sediment from three lakes have been obtained. The experiment results can give a good basis for improving water quality by the flocculation settling method.