Abstract: Current studies show that nature hail is less dense and tougher than clear ice, and cotton fibers are required to add to the simulated hail ice during the hail impact test on aeronautic structure saccording to ASTM F320-10, so as to accurately recurrent the mechanism properties of nature hail. To obtain the natural hail impact damage on composite skins, cotton fibers reinforced simulated hail ice impact tests on the rigid surface and composite panels were tested with the 80 mm caliber gas gun. The results show almost no influence of the freezing temperature on impact load peak. The elastic module and break strength of the simulated hail ice are of distinct enhancement, with the addition of cotton fibers. Delamination areas of composite panels are impacted by cotton-simulated hail ice vary with the velocity and stacking sequences, while no delamination is found for clear-simulated hail ice.