Abstract: Objective : To describ the data and trend, as well as to analyze the influential factors for the incidence of thyroid cancer in urban district of Tianjin. Methods : All cases of thyroid cancer in Tianjin Cancer Registry, during the period from January 1981 to December 2001, were used to describe the incidence of thyroid cancer, the incidence rate was computed on according to the related year population and gender and diagnosis time to study the changing situation. Results : Total of the thyroid cancer during 21 years is 1318. The papillary is the most common histological type. The median age of onset for thyroid cancer is 55 years old in male and 49 years old in female and the age of incidence in females is earlier than that in males significantly. The average incidence rate of thyroid cancer is 0.938 per 100,000 in males and 2.615 per 100,000 in females. The incidence rate of female is higher than that of males. Thyroid cancer incidence increased gradually with years among 21 years. The speed of increasing of females is higher than that of males. Conclusion : Quick increase of the incidence rate for thyroid cancer suggests that further researches on the risk factors and cancer-related health education should be performed, and the key monitoring and efforts for early prevention be made for the high risk women.