The litter and the residue of the aquatic plants play an important role in the nutrient cycle and energy flow. Under naturalconditions, the sediment was collected in situ at different stages of Eichhornia crassipes, and its changes of the litter and residue werestudied. The weight of sediment had an obviously increasing trend from waterhycinth death to its disappearance from water surface.When the litter and residue disappeared completely from water surface, the weight of sediment and the downward fluxes reached themaximum value 579.59g/m², 7.54g/(m²·d) respectively. Both of them had a significantly positive correlation with the watertemperature. When the litter and residue disappeared completely from water surface, the organic carbon, total nitrogen and totalphosphorus were low in the growth but high in the floating, and reached the maximum values 40.29%, 3.66%, 0.90% respectively,then they gradually decreased, and tended to be stable.