From statistical parameters of the bottom morphology and application of diagrams, as proposed by Sahu (1964), Passega & Beranjee (1969) and Pejrup (1988), the dynamic and sedimentary processes that occur in the Southern channel of the Amazonas river were characterized. The sediments that recover the bottom of the studied area are formed by medium quartz sand that grade, starting from the south river channel, to very fine silts in direction of the outlet of the Pará river, where happens a granulometric inversion. The hydrodynamic of the area is dominated by tidal and fluvial currents as well, partly due the action of winds which control these currents. These factors, associated with the estuarine circulation, are responsible for the transport, redistribution and deposition of the sediments in the Southern Amazonas river channel.