Objective: To investigate effectiveness of different intensities of basketball exercise on body compositions among obese junior middle school students, and to provide theoretical support for healthy weight loss among obese children and adolescents. Methods: From September to November 2020,a typical sampling method was used to select 48 obese junior middle school students were recruited from Wuhan Optical Valley Experimental Middle School according to body mass index(BMI), all the students were divided into high, moderate and low intensity basketball training group, as well as the control group, the 45 min per times basketball exercise intervention was administered three times per week for 12 weeks, while the control group did not received no intervention, body composition was assessed before and after intervention. Results: After 12 weeks of low intensity basketball exercise, the percentage of body fat of obese junior high school students after intervention was significantly higher than that before intervention[(32.16±2.26)% v.s. (34.33±2.35)%] ( t =3.52, P <0.05). There was no significant difference in other indexes body weight, body mass index, waist circumference, skeletal musclebetween before and after intervention ( t =2.31, 1.98, 1.26,-1.65, P >0.05). For moderate intensity basketball exercise group obdy weight, BMI, percentage of body fat and waist circumference showed statistical changes before and after intervention( t=3.44, 3.76, 6.56, 2.45, P <0.05). For high intensity basketball exercise group, all body composition indicators showed significant changes( t=4.14, 5.18, 11.26, 5.89, -2.56, P <0.05). Conclusion Twelve weeks of basketball exercise can effectively improve body composition of obese junior middle school students, with higher the intensity of exercise, the better the effectiveness.