Abstract: Experiments on sediment mixing characteristics under waves were carried out by using of a wave-flow-sediment flume. From experimental data, the vertical distributions of suspended sediment concentration (SSC) and vertical sediment mixing coefficients were determined under regular and irregular waves, respectively. It is found from experimental results that the vertical distribution of SSC agrees well with natural logarithm and the vertical sediment mixing coefficient may be described as εy=C1eD1Y.