Corrosion damage exists extensively in industries of national defense technology and transportation, which threatens seriously the safety and reliability of the structure. Therefore, it is of great significance to monitor corrosion damage for safety. In this paper, according to the theory of laser ultrasound, an automatic laser scanner detection experimental system is designed and developed. The laser scanning experiment was carried out on the corrosion damage in the aluminum plate through this system, and the relationship between the Lamb wave energy, amplitude and corrosion was analyzed, and visualize the damage area with the maximum amplitude according to the principle of "elastic wave energy flow method". Finally, we propose the amplitude integral ratio method, which can be used to evaluate the degree of corrosion damage, and the evaluation and analysis of aluminum plates with different corrosion degrees are completed. This research can realize the rapid detection and evaluation of corrosion defects, and the detection results are intuitive, showing a huge application prospect.