Objective To study the diagnostic value of CT and ultrasonography in the diagnosis of nodular goiter. Methods A retrospective analysis was performed on 100 patients with nodular goiter diagnosed by CT scan and B ultrasound scan. Ultrasound images were analyzed by ultrasound assistant chief physician and two ultrasound diagnostic physicians, and the results were compared with pathological findings. Results 100 cases were diagnosed as nodular goiter through pathological examination, including 24 cases of patients with thyroid cancer. The correct rate of CT diagnosis was slightly higher than that of ultrasonic diagnosis, but the difference was not statistically significant (P>0.05). The diagnostic accuracy of CT combined with ultrasound was significantly higher than that of CT or ultrasound group, and the difference was statistically significant (P<0.01). Conclusion CT and ultrasound have different advantages, so CT combined ultrasound can improve the diagnostic accuracy rate of patients with nodular thyroid disease.