A 3D numerical model of sediment transport and bed evolution of Caofeidian sea area under the combined forces of tidal current and wave was established based on Delft3D. This model was validated with the field measured tidal flow and sediment concentration in 2012. The validated model was used to simulate flow and sediment concentration fields and morphology evolution under the scenario of 2012. The responses of sediment transport and bed evolution were analyzed. The results show that: the sediment concentration in Caofeidian sea area is low, normally less than 0.2kg·m-3, its horizontal distribution presents higher in the west than in the east, and also in the nearshore and shoal areas than in the offshore area, while vertically increases from the surface to the bottom generally; the main erosions occur around Caofedian foreland, nearshore and shoals in the west and Dongkengtuo, the severe sedimentations appear in the western deep channels and Laolonggou creek. In general, the annual bed evolution is less than 0.5m and the morphology is stable with acceptable erosion and sedimentation rates.