| One important subject of coastal engineering is the sediment suspension, transportation and siltation. It's of great significance in both theoretical research and engineering design to study the distribution of suspended sediment concentration (SSC) in wave-current conditions. The previous studies on this subject were systematically summarized and classified in this paper, including exchanges between near bed sediment and suspended sediment, vertical profiles of suspended sediment, the carrying capacity and the sediment numerical simulation. Due to the complicated hydrodynamic conditions in estuary and coastal zones, and moreover, lacking field data or information, the formula obtained were different in different research area and can not agree with the real SSC distribution very well.With observed data obtained in two cruises, over a 15-day period separately in winter and summer of 2006, firstly, the hydrodynamic characteristics of the research area were analyzed, and then the characteristics of temporal and spatial distribution of SSC. Temporally, the SSC show a clear neap-spring tidal cycle and seasonal fluctuations. Besides, the interrelations between current (wave) and sediment concentration in a tidal cycle were also qualitatively described with diagrammatizing method. The vertical distribution of SSC was studied in detail, which also showed clear seasonal and tidal cycle fluctuation. Moreover, the exponential law, which described the velocity profile well, and a constant sediment diffusivityεz profile 0.85m above the bottom, were introduced to deduce the vertical profile formulae of SSC. The availability of the formula advanced by Zhang and Rouse was also tested and verified during the study. Finally, the empirical formulae of reference SSC was proposed from the observed data.
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