Abstract: Objective To examine the influence of smoking-free school activity on tobacco control knowledge and behavior among the teachers.Methods With stratified sampling method,two waves of questionnaire survey were conducted in March 2012 and March 2013 in 30 schools with smoking-free promotion activity in Beijing,Zhengzhou and Kaifeng city;totally 973 eligible base-line and 924 endpoint questionnaires were collected from the teachers in the schools.The tobacco control-related awareness and behaviors of the teachers were analyzed.Results The correct answer rate for eight questions about smoking hazards was 58.27%-95.99%for base-line survey and 71.10%-96.10%for endpoint survey among the participants,with the correct answer rates of 58.27%and 71.10%,6.71%and 78.30%,64.74% and 74.49%,and 62.38%and 72.29%for associations of smoking with vasculitis,sexual dysfunction in males,stroke,and osteoporosis for base-line and endpoint survey,respectively;all the correct answer rates in the endpoint survey were significantly higher than in the base-line(P<0.05 for all).For the participants at baseline and endpoint survey,the proportions of former smoker,current smoker,smokers with smoking cessation ideation,and smokers not smoking in school were 19.12%and 13.53%,56.99%and 36.80%,65.05%and 76.00%,and 23.68%and 39.20%,respectively,with significant differences in the rates between the two waves of the survey(P<0.05 for all).Conclusion The smoking-free school activity has positive influence on tobacco control knowledge and behavior among the school teachers.