The location and current & sediment conditions of Tonggu channel are described. According to the topographic survey data between 2008 and 2009, combining with the water and sediment environment in Tonggu sea, and from four aspects including the water depth’s change along the channel, scouring -siltation distribution, siltation volume and shape’s change of the cross section, this paper analyzes the temporal and spatial distribution of scouring-siltation in the channel, and calculates the annual quantity of back-silting and average siltation density of Tonggu channel. It is concluded that: the annual quantity of back-silting of Tonggu channel is about 5.73 million m3, the siltation density is about 0.82 m/a; and the siltation is characterized by more siltation in the flood season and less in the dry season, more siltation in the main groove and less in slopes.