Abstract: Objective： To study whether the socio-ecological model based on “student-school-family” three-level strategy is effective in obesity prevention.Methods: A total of 3 175 students aged 7 to 18 from 16 schools (4 urban primary schools, 4 rural primary schools, 4 urban secondary schools and 4 rural secondary schools, of which 2 intervention schools were selected, respectively ) were recruited by stratified cluster sampling method. A threemonth intervention using “student-school-family” socio-ecological model was conducted through health education and environment improvement. The intervention contents included knowledge on obesity, healthy diet and physical activities. Their anthropometric indexes were recorded. Results: The intervention prevented obesity(OR=1.12, P<0.05), and was effective in waist circumference (WC) and waist-hip ratio (WHR) (adjusted difference=0.63, 0.02, P<0.05). WC and WHR were reduced in girls (adjusted difference=0.52 & 0.02, P<0.05), and obesity was prevented in girls (OR=1.18, P<0.05). WC and WHR were reduced in boys (adjusted difference=0.73, 0.01, P<0.05). WHR were reduced in urban areas (adjusted difference=0.01, P<0.05). WC and WHR were reduced (adjusted difference=1.05, 0.02,P<0.05) and obesity was prevented (OR=1.18, P<0.05) in rural areas. WHR were reduced (adjusted difference=0.01, P<0.05) and obesity was prevented (OR=1.21, P<0.05) in primary schools. WHR were reduced in secondary schools (adjusted difference=0.02, P<0.05).The intervention effect was better in girls than in boys, in rural areas than in urban areas, and in primary schools than in secondary schools. The overweight and obesity prevalence went down after the intervention (χ2=11.01，P<0.01).   Conclusion:Intervention strategy is effective in central obesity indexes such as WC and WHR, and it can be used widely.

Key words: Obesity, abdominal, Early intervention(education), Students, Waist circumference, Waist-hip ratio