Objective: The purpose of this study was to explore the prevalence of thyroid nodules (TN) and metabolic syndrome (MS) and to analyze the correlation between TN and the components of MS. Methods: A total of 1526 subjects were divided into two groups: a TN group and a non-thyroid nodules (NTN) group. The height, weight, blood pressure, fasting blood glucose level, fasting plasma insulin level, serum lipid profile, uric acid level, serum thyroid-stimulating hormone (TSH) level, free triiodothyronine (FT3) level, and free thyroxine (FT4) level of each patient were measured. Insulin resistance (IR) was estimated by homeostasis model assessment of insulin resistance (HOMA-IR). Fatty liver and TN were detected by color Doppler ultrasonography. Results: (i) The overall prevalence of TN was 39.5%; it was significantly higher in women than in men (P < 0.01) and progressively increased with age in both sexes. (ii) The overall prevalence of MS was 25.6%; it was significantly higher in men than in women (P < 0.01) and progressively increased with age in both sexes. (iii) FT3 was significantly lower in the TN group than in the NTN group (P < 0.01). (iv) BMI, triglycerides, and HOMA-IR were higher in the TN group than in the NTN group (P < 0.05). (v) The existence of TN was significantly associated with overweight/obesity (OR = 1.03, 95% CI = 1.024–1.089), and with insulin resistance (IR) (OR = 1.98, 95% CI = 1.645–2.368), after adjusting for age and sex. Conclusions: The prevalence of thyroid nodules and metabolic syndrome in the Nanchang area increases with age, and overweight/obesity and IR in patients are associated with thyroid nodules.