Objective To investigate the factors affecting the occurrence of thyroid nodules,and to offer scientific methods to prevent the occurrence of this disease.Methods A total of 220 subjects were involved in the study from January 2012 to December 2014 at the Affiliated Hospital of Shanxi Institute for Endemic Disease Prevention and Treatment.A case-control study was designed.The case group with thyroid nodules was confirmed by color Doppler ultrasonography and pathology.The control group,at the same time,was confirmed by ultrasound and thyroid function tests.Face to face questionnaire was used to collect the demographic data,family history of disease and thyroid function test results.The differences in general conditions,living habits,family history,and clinical test results were compared between the two groups.Finally,multivariate logistic regression model was used to analyze risk factors,which may affect the occurrence of thyroid nodules,odds ratio (OR) was calculated.Results This study collected 209 valid samples.The rate of valid samples was 95.00％ (209 / 220).The average age was (42.28 ± 11.86) years old,and the ratio of male to female was 1.0 ∶ 5.3 (33 ∶ 176).There were significant differences in age,sex,body mass index (BMI),the use of hair dye,total thyroid thyroxine (TT3),serum free thyroxine (FTg),and thyroid-stimulating hormone (TSH),anti-thyroid microsomal antibodies (TMAb) between the case group and the control group (P ＜ 0.05).Those variables,which were significant in single factor analysis such as age,gender,BMI,hair dye,TT3,FT4,TSH and TMAb,were put into the logistic model to adjust confounding.After that,the results suggested that the risk increased 9.7％ [OR:1.097,95％ confidence interval (CI):1.017-1.183] with increase in age by one year.Women were 3.214 times (OR:3.214,95％CI:1.025-5.923) more likely to have thyroid nodules.TSH increased by 1 level,the risk increased by 1.030 times (OR:2.030,95％CI:1.050-3.922).TMAb increased by 1％ on average,an increase in the risk of disease by up to 28.3％ (OR =1.283,95％CI:1.076-1.529).Conclusions Women are at higher risk of thyroid nodules than men.And older age,high levels of TSH and TMAb also increase the risk of thyroid nodules.