The article sums up 4 main influencing factors of hydraulic fill sediment loss rate in dredging engineering based on the theory of fluid mechanics and a large number of engineering monitoring data,ie.soil particle size,filling quantity,effective capacity and flow path.The paper also analyzes the relationship between the 4 factors and the relationship between the 4 factors and sediment loss rates qualitatively or quantitatively based on the principles of statistics,and fits out the theoretical formula related to the sediment loss rate using the numerical analysis method.According to the results of the analysis the article puts forward specific measures to control dredging and filling engineering’s sediment loss rate.It may serve as reference for optimizing the dredging technology and cutting down the construction cost.