The modern sedimentary environment in the Yangshan Harbor sea area is mainly controlled by topography, material sources and hydrodynamics. Modern sediments consist mainly of silt and clay particles, and are transported primarily by suspension and secondarily by saltation. Moving and saltation processes of the modern sediments are alternated frequently. The long-term net transport trends of the modern sediments indicate that some sediments from Huangzeyang entered the Yangshan Harbor area, the deep trough of the channel was formed by the transport of sediments of the west and east parts of the channel towards its two ends respectively, and the area between Xiaoyangshan and Tangnaoshan is an convergent area of sediments, which will be an siltation area of the Yangshan Harbor in the future.