Background and Objectives: The relationship between nutritional status of iodine and thyroid tumor is unclear. We investigated the association between urinary iodine concentration and thyroid function in patients with papil- lary thyroid cancer, benign thyroid tumor and healthy individuals. Methods and Study Design: We compared the biomarkers of thyroid function and urinary iodine concentration within and between each group. A regression analysis was used to identify risk factors for papillary thyroid cancer. Correlation analysis was performed to de- termine whether any significant correlation exists between urinary iodine concentration and thyroid function bi- omarkers. Results: The iodine nutrition statuses of these three groups were adequate (median urinary iodine con- centration=100–199 μg/L). However, the median urinary iodine concentration of papillary thyroid cancer (174.7 μg/L) and benign thyroid tumor (165.04 μg/L) groups was significantly higher than that of the healthy control group (135.8 μg/L) (p<0.05). The regression analysis showed that thyroglobulin antibody was an independent risk factor for papillary thyroid cancer. After adjusting for age and gender, the association between thyroglobulin an- tibody and urinary iodine concentration was significant (β: 0.002; p<0.05). In subgroup analyses, significant cor- relations was noted only in the papillary thyroid cancer group (adjusted β: 0.002; 95% confidence interval: 0.000– 0.003). Conclusions: Excessive iodine in patients with thyroid tumors may affect thyroglobulin antibody, which may be an independent risk factor for papillary thyroid cancer.