Abstract: 90:10 cupronickle alloy (CDA706) would lose its corrosion resistance and/or antifouling property in seawater under certain condition of process technology although the alloy is well known to be excellent in both properties.It was discovered in present work that plate specimens processed by different surface treatment as well as different deformation and annealing technology shown much different antifouling properties. The specimens were put into seawater in Yulin experiment station for seawater corrosion. After 6 months exposure the organism amount attached on the plate specimens were vastly different, the best specimen possessed both good corrosion resistance and antifouling properties was the one processed by 650℃ annealing treatment and pre treatment of surface film after a suitable deformation. But the specimens processed by 450℃ annealing and different amount of deformation and even surface pretreatment exhibited relatively poor corrosion resistance.Yet the antifouling properties of this series of specimens were influenced by deformation. The corresponding relationship between the microstructure and the properties of the alloy specimens was investigated through observation under electron microscopy.