Abstract: ObjectiveTo examine the prevalence and relevant knowledge and attitude about second hand smoking(SHS)among adult residents in Shizhong district of Ji'nan city,Shandong province and to provide evidences for developing policies of tobacco control.MethodsA face-to-face questionnaire survey was conducted among 2 497 residents aged 18 to 69 years selected with random cluster sampling from two household committees of a community in Shizhong district of Ji'nan city.ResultsThe smoking rate was 33.04% and the SHS rate was 60.35% among the residents.There were significant differences in the SHS rate among the residents of different gender,age,education level,and occupation (all P<0.001).Of the residents with SHS,18.18%,27.27%,and 54.55% reported the SHS frequencies of 1-3,4-6,and almost 7 days per week,with a significant difference (χ²=17.529, P<0.001) and 12.08%,77.90%,and 10.02% reported home,work place,and vehicles being the main place of SHS,also with a significant difference (χ²=19.026, P<0.001).Among the residents surveyed,63.12%,65.24%,and 77.77% had the knowledge about SHS being related to the incidents of cardiovascular diseases,lung diseases in the children,and lung cancer; the ratios of the residents supporting the regulation of no smoking in public and work places were 67.08% and 69.84%.ConclusionThe SHS is relatively high among the adult residents in Shizhong district of Ji'nan city and tobacco control should be promoted among the residents.