The atomization rainfall induced by flood discharge of large hydraulic projects, especially those with ski-jump energy dissipater, is far more intense than natural rainfall, harmful for the project's normal operation, traffic safety, and surrounding environment. In this article, prototype observation is carried out to research the atomization influence scope, rainfall intensity distribution, and meteorological characteristics during the deep-hole discharge of Xiluodu hydraulic project in the downstream of Jinsha River. Results suggest that distributing in some local positions, the atomization rainfall intensity at Xiluodu hydropower project decreases rapidly along longitudinal and bank slope directions. In observation condition, the maximum intensity reaches 4 704 mm/h; when natural wind speed is smaller than 3.5 m/s, the maximum wind speed in flood discharge area is up to 16.3 m/s; and when natural air pressure and humidity are 0 kPa and 85% respectively, the maximum air pressure and humidity in flood discharge area reaches 96 kPa and 100%,respectively. The observation results could be used to verify the design of bank slope protection for Xiluodu hydropower project, and also provides rich and detailed data for other research approaches.