Abstract: Based on the analytic results of bottom sediment samples, combined with sediment texture,topography and hydrodynamic conditions, a new triangular diagram advanced by Flemming is applied to reveal the sediment characteristics and sediment environment in the Lianyungang coast. The results indicate that the study area which is mainly affected by tidal current can be divided into two sedimentary environments:the nearshore zone and the offshore zone. In the nearshore zone, the tidal current decreases its strength from sea to land. As a result, sediments conveyed by tidal current become less concentrated and the grain size of the sediments gets finer. The sediments are dominated by clayey silt and sand-silt-clay. In the offshore zone, due to the strong tidal current, fine sediments can be lifted and transported to the nearshore zone, and sediments in this zone have a tendency of getting coarser.