Objective To compare the features of purely thyroid cancer and thyroid cancer complicated with benign lesions. Methods 325 thyroid cancer patients diagnosed by pathology from November 2016 to November 2017 were enrolled in the study. The ultrasound characteristics were analyzed. Results Statistically significant differences were observed in the calcification type between purely thyroid cancer and thyroid cancer complicated with benign lesions (P＜0.05). The rate of solid nodules in purely thyroid cancer were significantly higher than those in thyroid cancer complicated with benign lesions (P＜0.05). Statistically significant differences were also observed in the rate of irregular capsule among purely thyroid cancer , thyroid cancer with nodular goiter, thyroid cancer complicated with both Hashimoto's thyroiditis and nodular goiter (P＜0.05). The rate of irregular capsule in thyroid cancer complicated with Hashimoto's thyroiditis were higher than those in thyroid cancer with nodular goiter (P＜0.05). The rate of Blood flow signal Ⅲin purely thyroid cancer were higher than those in thyroid cancer with nodular goiter (P＜0.05). The thyroid cancer complicated with Hashimoto's thyroiditis had more Blood flow signal Ⅲ than thyroid cancer with nodular goiter, and thyroid cancer thatcomplicated with both Hashimoto's thyroiditis and nodular goiter (P＜0.05). There were statistically significant differences in the rate of calcification between purely thyroid cancer and thyroid cancer with nodular goiter (P＜0.05). The rate of macrocalcifications in thyroid cancer complicated with Hashimoto's thyroiditis were higher than those in purelythyroid cancer (P＜0.05). The ultrasound diagnosis of metastatic lymph node in thyroid cancer sensitivity and specificity were 26.27% and 92.53%. Conclusion There are differences in Ultrasound characteristics such as calcification, capsule , blood flow signal between purely thyroid cancer and thyroid cancer complicated with benign lesions. Purely thyroid cancer may have poor prognosis than thyroid cancer complicated with benign lesions. The ultrasound characteristics of thyroid cancer complicated with benign lesions were not typical as purely thyroid cancer may causes misdiagnosis and missed diagnosis.