Abstract: Objective To explore influencing factors of papillary thyroid carcinoma for making strategies for the prevention of the disease.Methods A 1:2 matched hospital-based case-control questionnaire study was carried out among 123 papillary thyroid carcinoma patients receiving surgery in Fujian Provincial Tumor Hospital between April 2013 through June 2014 and 246 controls having health examination at the hospital during the same period.Results Compared to those of the controls,the cases had significantly higher proportions for with the body mass index (BMI)>25.0 kg/m² (14.63% vs.6.10%),time of second-hand smoking (54.47% vs.46.34% for 1-2 day/week,33.33% vs.19.92% for ≥3 day/week),frequency of hair dying (62.60% vs.42.28% for 1-2 times/year,4.88% vs.2.03% for ≥3 times/year),eating fried food>5 times/week (28.46% vs.15.85%),eating cruciferous vegetables >5 times/week (50.41% vs.33.74%),having computed tomography (CT) ≥3 times (12.20% vs.5.69%),with high stress (20.33% vs.10.57%),with his or her first degree relative having history of thyroid cancer (9.76% vs.1.63% for one relative,6.50% vs.1.22% for two or more relatives),respectively,and lower proportion for having physical exercise 1-2 times/week (10.57% vs 21.54%)(P<0.05 for all).Multivariate conditional logistical regression analysis indicated that BMI ≥25 kg/m²,second-hand smoking ≥1 day/week,hair dying ≥1 time/year,having CT ≥3 times,having high stress,and having first degree relative with thyroid cancer history were risk factors of papillary thyroid carcinoma;while having physical exercise 1-2 times/week was a protective factors.Conclusion BMI,second-hand smoking,hair dying,CT examination,thyroid cancer history in first degree relative,stress and physical exercise were main influencing factors of papillary thyroid carcinoma.