Abstract: To understand the effects of enclosed exercise for weight loss on physical health of obese adolescents. The 44 cases of 14 to 19 year-old obese adolescents were chosen by us in 6-week enclosed exercise for controlling diet and exercise. Their indicators of body shape, body function, physical fitness, blood health and so on were tested. By means of literature analysis and mathematic statistics to analyze the mathe of experiments. The results showed that through six weeks of enclosed exercise, The obese adolescents have a significant decline in fat mass, weight, body fat rate(P<0.05). Lung capacity of obese adolescents gradually increased, physical fitness indicators endurance, flexibility, 50-metre Race and blood health indicators triglyceride(TG), total cholesterol(TC), fasting insulin(FINS) were significantly improved(P<0.01). The enclosed sports weight loss on the physical health o the obese adolescents good performance.