Objective: This study aims to investigate the selective protective effect of hydrogen water on the free radical injury of athletes after high-intensity exercise and to provide a reliable method for reducing oxidative stress injury of athletes. Methods: A total of 60 athletes from the swimming team in our city were selected as the research subjects. They were divided into the control group and hydrogen water group according to different intervention methods. The athletes in the control group were treated with placebo, and the athletes in the hydrogen water group were supplemented with hydrogen water. The serum superoxide anions, Serum Superoxide Dismutase (SOD) activities, and total antioxidant capacities of athletes were compared between the two groups. Results: The serum superoxide anions, serum SOD activities, and total antioxidant capacities of athletes during and after training were significantly superior to those of the control group (P<0.05), and the difference was statistically significant. Conclusion: Hydrogen water supplement could effectively reduce the oxidized substances in athletes before, during, and after exercise and could prevent the free radical injury caused by high-intensity exercise.