Abstract: The paper analyzes the effect on the body shape and body composition of primary school pupils and tries to explore a means to prevent and control obesity. Methods: a total of 430overweight / obese students are selected randomly from four primary schools as experimental intervention targets. They are divided into groups of aerobic, anaerobic group, consolidated group and the control group. The experiment lasts for 16 weeks with five days of exercise per week and about 65 minutes every day. The exercise intensity is controlled within the target heart rate range. Results: after 16 weeks of exercise intervention, their waist circumference, hip circumference and body fat percentage significantly decrease (p <0.05), while their body weight and level of intervention on this indicator have no interaction (p> 0.05). Their waist circumference, hip circumference and body fat percentage is significantly affected by the intervention (p <0.05). Conclusion: the 16 weeks of school-based exercise intervention approach can significantly reduce the pupils' waist, hip and other body morphology index, but there are no significant changes in body weight. Aerobic-based exercise is best. Exercise intervention can significantly reduce the body fat percentage of primary school pupils, improve their body composition; role of aerobic exercise maximum.

Key words: body shape, body composition, exercise intervention, mixed linear model