Abstract: The corrosion behaviors of nine kinds of copper alloy, exposed in nature silt seawater of Zhoushan for 1,2,4 and 8 years, were reported. The influences of silt in seawater on the corrrosion behavours of the copper alloys were inverstigated by in door accelerated corrosion test in clear seawater and in seawaters with silt of 0.75‰, 1.5‰ respectively, and the specimens were examined visually and microscopically and their corrosion rates were measured. The result shows that the nature silt in following seawater can accelerate the corrosion of the copper alloys but the influences of silt content on the corrosion rate of nine copper alloys are quite different.