Abstract: Based on the data of underwater topography, hydrology, and remote sensing images, this paper comprehensively uses remote sensing, geographic information system ,surface sediment analysis and other technical methods to analyze the characteristics of hydrodynamic, deposition and geomorphology in Changsha bay, which is located in the east coast of Guangdong Province, China. The results indicate that the tidal current outside the bay is relatively weak. The coastal current outside the bay is mainly from West to East in summer and from East to West in winter. The middle east of the bay mouth is dominated by flood current, while the west side is dominated by ebb current. The major flow inside the bay is biased towards the East. There are two convergence areas of surface sediment transport in the bay, one of which is located in the nearshore area on the right side of the outlet of Huangjing river, and the other is located in the middle of the bay. The outlet of the Huangjiang river is characterized by beach deposition and trough erosion. The siltation intensity of the shoals on the right bank of the estuary and the east of the middle of the bay is relatively large, and the section of the bay mouth remains basically stable. The seabed sediment convergence area indicated by the surface sediment is in good agreement with the seabed siltation area reflected by the topographic data. There is a sediment transport from the middle to the East and West sides at the top of the bay, which is the main reason for the continuous siltation of the shoal on the right bank of the outlet. The central part of the bay is the area where the predominance of tidal current changes, and the sediment is easy to fall and deposit, leading to continuous siltation in this part. The causes of siltation above are basically consistent with the transport path of bed sediment indicated by the surface sediment in these two zones. There are many bays in the east of Guangdong Province with medium or small rivers flowing into them, and the hydrodynamic, deposition and geomorphology process of the outlet is similar to the study area.This study not only has important theoretical significance for understanding the complex dynamic structure and evolution characteristics of the bay, but also has practical value for environmental protection and development and management of the bay.