Objective   To examine the attitude towards smoke-free law in public places and its influencing factors among citizens in Shenzhen city and to provide evidences for promoting the effective implementation of the law.

  Methods   We selected 274 public places in 10 jurisdictions of Shenzhen municipality with proportional random sampling and then intercepted 10 citizens aged 15 – 70 years in each of the public places for a questionnaire survey between January to February 2016.

  Results   Of the 2 708 eligible responders, 86.78% were in favor of smoke-free law in public places. Multivariate logistic regression analyses showed that gender (female vs. male: odds ratio OR = 1.68), education (senior high school vs. junior high school and below: OR = 1.86; undergraduate and above vs. junior high school and below: OR = 2.38), score for knowledge about smoking (4 – 6 points vs. 0 – 3 points: OR = 1.78; 7 – 8 points vs. 0 – 3 points OR = 2.46), scores for knowledge about smoke-free law (3 – 4 points vs. 0 – 2 points OR = 1.51), and smoking status (non-smoker vs. smoker: OR = 3.75) were the influencing factors for the attitude towards smoke-free law in public places (all P < 0.05).

  Conclusion   The rate of support for smoke-free law in public places is high among citizens in Shenzhen city and interventions on factors related to attitudes towards the law among the public may promote effective implementation of smoke-free law in public places.