Abstract: The water and sediment movement in the Qiantang River estuary is extremely complex. The problems of the sediment transport has always been concerned by scholars. However, it is very difficult to observe the sediment concentration in the tidal reaches of the estuary, and there is a relative lack of systematic measurement analysis and research on the law of sediment concentration. In order to improve the understanding of water and sediment characteristics in the Qiantang River estuary, the measured sediment concentration at Yanguan tidal gauge station for several consecutive days from April to June 2022 was analyzed and studied based on the background of the cofferdam project to be built in Haining section on the north bank of the Qiantang River before the main flood season. Firstly, the data of sediment concentration were divided and analyzed according to the tidal range level (spring tide, middle tide, neap tide) and tidal time (before flood tide, flood tide, slack tide, ebb tide). Secondly, the measured sediment concentration was fitted with the turbidity data obtained from Yanguan tidal gauge station in the same period. Two groups of fitting curves were obtained according to the level of tidal range and turbidity interval, and the correlation degree was around 0.9. The fitted curve was verified and then applied in the analysis of relationship between the tidal level and the sediment concentration in July. The results showed that the dispersion degree of sediment concentration during spring tide was the largest, followed by middle tide and neap tide. There was little change in sediment concentration during neap tides. The sediment concentration increased obviously during middle tide and spring tide, and decreased during slack tide at high level before returning to the original sediment concentration during ebb tide. Overall, sediment concentration curve and tidal curve had similar periodic process. It was noted that the sediment concentration showed a small rise during ebb tide period, which might be because the flow velocity increased after the slack tide period and some settled sediment moved again with flow. This study will enhance the understanding of sediment transport in the Qiantang River estuary, which helps to solve the sediment problems in the estuary engineering.