Abstract: According to the measured data of sea current and suspended sediment in Longkou Bay, the temporal and spatial distribution patterns and the variation of suspended sediment concentration in the study area were discussed in order to explore the transport mechanism of suspended matter with Morlet wavelet analysis and decomposition method of unit-width suspended sand flux. The results show that, horizontally, the concentration of suspended sediment outside the artificial island is larger than that within the island. Vertically, the average sediment concentration of each station decreases obviously from the bottom to the surface layers. The variation of suspended sediment concentration in the tidal cycle is complicated. The concentration of suspended sediment in each station generally shows 2~4 peaks in a single day; the peak concentration of suspended sediment tends to lag behind the peak value of flow rate for half an hour to two hours; and the change cycle of suspended sediment concentration is basically 12~16 h. The unit-width sediment transport flux in the study area mainly ranges from 2.64 to 24.68 gs^-1m^-1. The overall distribution of suspended sand flux outside the artificial island is higher than that within the artificial island. The direction of suspended sediment transport is basically consistent with the direction of the tidal residual current. Due to the influence of residual current, topography and suspended sediment concentration, the contribution of each sediment transport to the sediment transport rate is quite different, and the advection transport has an absolute advantage in suspended sediment transport, followed by vertical net circulation sediment transport.