With rapid industrial progress, the material damage by severe corrosive environment and cavitation are emerging as a major issue. To solve this problem, various researches on design changes, addition of inhibitor, material improvement, and cathodic protection are being conducted. The water cavitation peening technique, especially, is a prominent surface modification technology which introduces compressive residual stress for surface using local breakdown impact pressure of cavities. While the application of cavitation has advantage in the improvement of material performance, it damages materials if it is excessive. Various factors are associated with such material damages, including flow, pressure, temperature, and amplitude of vibration. This study examined the degree of cavitation damages with various seawater temperatures and ultrasonic amplitudes for the aluminum alloy 5083-H116. The experiment results indicated that weightloss increased with the increase in seawater temperatures, ultrasonic amplitudes, and experiment time.