Objective To study the diagnostic effect of Chinese ultrasonic thyroid imaging reporting and data system (C-TIRADS) combined with elastography on the nature of thyroid nodules based on ultrasound, so as to provide reference for clinical diagnosis of the nature of thyroid nodules. Methods 50 patients with thyroid nodules admitted to The People’s Hospital of Rugao from January 2021 to December 2021 were selected for retrospective analysis. A total of 95 nodules were pathologically diagnosed, which were divided into benign nodules group (33 nodules) and malignant nodules group (62 nodules) according to pathological diagnosis. The patients were examined under ultrasound and the nature of the nodules were determined according to the C-TIRADS classi?cation system. The C-TIRADS classi?cation and ultrasound elasticity score were compared between the two groups. The pathological diagnosis results were taken as the gold standard, and the ef?cacy of C-TIRADS, elastography and their combination in the diagnosis of thyroid malignant nodules were compared. Results The proportion of C-TIRADS classi?ed into 3 categories in benign nodules group were signi?cantly higher than that in malignant nodules group, and the proportion of C-TIRADS classi?ed into 4B and 4C categories were signi?cantly lower than that in malignant nodules group (P<0.05). There were no signi?cant differences between the two groups in the proportion of C-TIRADS classi?ed into 4A and 5 categories (P>0.05). The proportion of thyroid nodules with ultrasonic elasticity score of 2 in benign nodule group were signi?cantly higher than that in malignant nodule group, and the proportion of thyroid nodules with ultrasonic elasticity score of 4 and 5 were signi?cantly lower than that in malignant nodule group (P<0.05). The consistency analysis con?rmed that the sensitivity, speci?city and accuracy of C-TIRADS classi?cation in the diagnosis of thyroid malignant nodules were 77.42%, 90.91% and 82.11% respectively. The sensitivity, speci?city and accuracy of elastography in diagnosing thyroid malignant nodules were 70.97%, 87.88% and 76.84% respectively. The sensitivity, speci?city and accuracy of C-TIRADS classi?cation combined with elastography in the diagnosis of thyroid malignant nodules were 87.10%, 90.91% and 88.42% respectively. Conclusion Both C-TIRADS classi?cation and elastography can be used for the diagnosis of benign and malignant thyroid nodules. However, the combination of C-TIRADS classi?cation and elastography has a good diagnostic effect and high accuracy, which is worthy of clinical application.