Nickel-alloy turbine was corroded after worked for a period of time. The size of turbine blades became smaller. Through observation, testing, the corrosion reason of the tubine was found. The results show that the corrosion was sodium salt hot-corrosion. The oxide was fell off which made the size of turbine blade became samaller. Because the fuel oil was not burned all, some sodium-salt deposited on the turbine's surface, which made the tubine corroded.