Objective To investigate the interactive effects of obesity and breast feeding on asthma and asthma related symptoms among children. Methods Using a cluster random sampling method, 1 elemen-tary school and 2 kindergartens were randomly selected from each district of Shenyang. A total of 5 elementary schools and 10 kindergartens were included. The information about obesity and the type of breastfeeding, living environment and respiratory diseases were collected by an international standard questionnaire from American Thoracic Society while measuring physical system of children. Results A total of 9335 questionnaires were distributed to all the students enrolled in the selected schools, and 8371 completed questionnaires which collect-ed with a response rate of 89. 7%. Finally, 8212 questionnaires were used for further analysis with a qualified rate of 98. 1%. The percentage of overweight and obesity among children are 12. 7% and 15. 5% respectively. The percentage of breastfeeding was 78. 9%. The prevalence of obesity children with asthma (8. 5%) is nota-bly higher than normal children (5. 8%) with a significant difference (χ2 =13. 48, P=0. 0012), while the prevalence of breastfeeding children with asthma ( 6. 05%) is notably lower than non-breastfeeding children (7. 38%) with a significant difference (χ2 =4. 05; P=0. 04). Multivariate factor analysis showed that com-pared with normal weight children, obesity of breastfeeding children increased asthma risk by 38% ( OR =1. 38, 95%CI=1. 05 ~1. 82); while in non-breastfeeding children, obesity increased the risk of asthma by 56% (OR=1. 56, 95%CI=0. 99 ~2. 44). Further analysis showed obesity and breastfeeding for persistent phlegm and current wheeze in children. Conclusion Breastfeeding can significantly reduce the overweight obesity of children with asthma and asthma-like symptoms, and there is a significant impact on interaction.