Objective: To retrospectively characterize and analyze the thyroid ultrasound images of thyroid cancer patients, to classify thyroid nodules according to thyroid imaging reporting and data system (TI-RADS), and to evaluate the diagnostic value of TI-RADS. Methods:Clinical data of 160 thyroid cancer patients with 235 nodules from September 2008 to August 2011 were retro-spectively analyzed. All patients underwent conventional color Doppler ultrasonography to evaluate the size, number, shape, boundary, and extent of lesions and blood distribution of the nodules. All nodules were analyzed according to TI-RADS classification and scored to evaluate the diagnostic value of TI-RADS. Results:Among 176 malignant nodules, 144 (81.8%) had lesions showing a mass of irreg-ular boundary with no envelope and halo, 152 (86.4%) were inhomogeneous hypoechoic or slightly hypoechoic, or 144 (81.8%) exhibit-ed microcalcification. TI-RADS scores of 4 or 5 and 2 or 3 were obtained in 160 (90.91%) and 16 (9.09%) of the malignant nodules, re-spectively. Conclusion:Thyroid ultrasound sonogram of ill-defined, irregular shape, hypoechoic or slightly hypoechoic mass, microcal-cification within the mass, and rich blood flow is an important index for the diagnosis of thyroid cancer. Thyroid nodules with a TI-RADS score 4 or 5 have higher possibility for cancer. Therefore, TI-RADS has a significant diagnostic value for thyroid cancer be-fore operation.