This paper focuses on the relationship between the movement characteristics of flow(and suspended sediment)and erosion(and deposition)near bottom in the deep navigation channel of the north passage in the Yangtze estuary. Based on the model for calculating the sediment flux near the bottom and observation data,the key parameters,such as the settling velocity and settling probability of sediment,are selected and calibrated. Eventually the calculation model for back-siltation in the deep navigation channel of the north passage is established and discussed. The calculated results by this model fit well the measured data.