The influence of annealing on the formation of nanocrystalline of CuNi alloy surface was investigated by evaluating the microstructure, mechanical properties, and corrosion behavior of as-processed condition (using severe plastic deformation by punching process) and its annealed condition. It was observed that the microstructure changed after annealing of punched sample using an atomic force microscope. Mechanical resistance and corrosion resistance were also characterized using nanoindentation test, electrochemical test, electron work function, and microtribometer test. It was found that the punched and subsequent annealed samples have increasing hardness, elastic behavior (η), and corrosion resistance. Therefore, annealing can lead to the final formation of nanocrystalline and corresponding stability of grain boundary, which are responsible for the increasing mechanical properties and corrosion resistance. The influence of annealing on the formation of nanocrystalline of CuNi alloy surface was investigated by evaluating the microstructure, mechanical properties, and corrosion behavior of as-processed condition (using severe plastic deformation by punching process) and its annealed condition. It was observed that the microstructure changed after annealing of punched sample using an atomic force microscope. Mechanical resistance and corrosion resistance were characterized using nanoindentation test, electrochemical test, electron work function, and microtribometer test. It was found that the punched and subsequent annealed samples have increased hardness, elastic behavior (η), and corrosion resistance. Thus, annealing can lead to the final formation of nanocrystalline and corresponding stability of grain boundary, which are responsible for the increasing mechanical properties and corrosion resistance.