In order to study the water and sediment variation trend, changes in sediment deposition and erosion and spatial distribution of Lake Hongze, the methods of cumulative anomaly, Mann-Kendall trend and mutation test, and R/S analysis were used to analyze the water and sediment characteristics of Lake Hongze from 1950 to 2016. Using geographic information technology, based on the terrain of the lake area in 1992 and 2016, the spatial distribution of sediment erosion and siltation was quantitatively calculated and analyzed. The results show that, on the premise of no increasing or decreasing of the flow rate, the sediment transport and concentration show an obvious decreasing trend. After 1990, the sediment concentration has stabilized below 0.2 kg/m³; The amount of water and sediment flowing into the mainstream of the Huaihe River (including the Chihe River) accounts for about 89.6% of the total amount of water flowing into the lake, and the outflow of Sanhe Sluice accounts for 60% of the total outflow. The main sedimentary areas of the Lake Huaihe inlet and Lihewa are the sedimentation volumes of 2300×10⁴ and 1900×10⁴ m³, and the average sedimentation thickness is 0.35 and 0.25 m, respectively; Basic balance of natural erosion and deposition in other areas. The effects of the upstream reservoir sediment blocking, agricultural planting changing underlying surface, and artificial sand mining are the key reasons for the continuous decline of sediment concentration entering the lake. The hydrodynamic characteristics of the lake area are the dominant factors for the natural sedimentation of the sediment, while the main reasons for the change in the storage capacity of the lake area are artificial sand mining, lake farming, and seine culture, and the impact of human activities is far greater than that of natural erosion and deposition.