Abstract: The tidal pattern of the east entrance of Qiongzhou Strait is irregular diurnal tide, which is characterized by east-west reciprocating flow, and the strong tidal current is the main dynamic factor to shape the seabed geomorohology. The study of sediment transport characteristics under tidal current is crucial for better understanding the fluxes of water and sediment, sedimentary processes and geomorphological evolution at Qiongzhou Strait. The survey data show that the sediments at the east entrance of the strait are mainly sandy and gravelly, which form the bed load transported on the seabed. In order to study the sediment transport and seabed geomorphology, the tidal current process, sediment transport rate and erosion and sedimentation intensity of the east entrance of Qiongzhou Strait are estimated by the sedimentary dynamics models. The results show that the maximum eastward flow is between 0.9 and 2.0 m/s, and the maximum westward flow is between 0.8 and 1.7 m/s, and the tidal flow in the middle and neap tides is roughly 50% to 60% of that in the spring tides. In general, the eastward flow is stronger than the westward flow, but in the north and the middle part of Qiongzhou Strait, the westward flow is always stronger than the eastward. During spring tides, the frequency of sediments movement in the study area is generally high, with an average of 60%, and the average transport rate is 10⁻² kg/(m·s). During the middle and neap tides, the average frequency is only about 18%, and the average transport rate is 1-2 orders of magnitude smaller than that during the spring tides. The sediment transport direction is mainly eastward. It can be seen that there is a higher accumulation rate nears the shoals and a higher erosion rate, which can be reach 10⁻¹ m/a.