Objective   To realize the level, source and demand of knowledge on smoking and health in secondary school students.

  Methods   Self-administered questionnaires were used in a cross-sectional survey to collect smoking related information of 8 656 secondary school students.

  Results   According to the percentage of correct responses, diseases caused by smoking were ranked as follows: lung cancer, chronic bronchitis, emphysema, chronic pulmonary heart disease(CHPD), mouth cancer, larynx cancer, coronary heart disease, hypertension, gastric ulcer and stroke.The percentage of correct responses for tobacco tar was the highest, followed by nicotine, then carbon monoxide and hydrocyanic acid.Health workers served as the most reliable source to provide knowledge on smoking and health.Only 38.9% of the respondents reported having ever been exposed to anti-smoking propaganda, according to whose opinions television and advertisement were the two most impressive methods of propagandizing.Among the respondents, 64% of them showed their wishes to know more knowledge about smoking and health.Their most favorite method to get smoking related knowledge was through television and broadcast.Damage of smoking to health was the prior knowledge that they needed.

  Conclusion   In order to improve the effectiveness of education on smoking and health for adolescents, health workers should be involved as much as possible.The knowledge on smoking and cardiovascular and cerebrovascular diseases should be added and emphasized.Televisions and advertisements are supposed to be effective education methods.