Abstract: Objective To explore different ultrasonographic methods for benign and malignant thyroid nodules and their clinical significance in differential diagnosis.Methods A group of 250 patients with thyroid nodules were examined by Color Doppler ultrasonography before operation.And the ultrasonographic images of calcification and pathological results were compared.Results The calcification rate(67.60%) as well as the detection rate of blood flow in malignant group was significantly higher than those in benign group.In under-45-year-old patients,the calcification rate of the malignant thyroid nodules was 88.46%,the differences were statistically significant as compared with those in over 45-year-old patients.There was no significant difference found between the ultrasonographic diagnoses (according to the calcification rate) and the pathological results.The sensitivity of ultrasonography was 67.60%,and the specificity was 83.24%.Conclusion Ultrasonography is a good method to distinguish between malignant and benign thyroid nodules.