Objective To investigate the value of three-dimensional shear wave elastography (3D-SWE) combined with ultrasonographic subcategorization of Breast Imaging Reporting and Data System (BI-RDS-US) in qualitative diagnosis of breast nodules. Methods A total of 120 female patients with breast nodules who were admitted to the hospital from January 2020 to March 2022 were selected. The properties of their lesions were confirmed by pathology, and all subjects underwent conventional ultrasound (US) examination. The Bi-MADS-US classification standard was used to judge benign and malignant nodules.3D-SWE was performed to measure the maximum elasticity (Emax) of the hardest part of the nodule and the elasticity ratio of surrounding adipose tissues (Eratio) on different planes of benign and malignant nodules. With pathological results as the golden standard, diagnostic efficacy of the two methods for breast nodules was comparatively analyzed. Results Pathological results showed that there were a total of 120 lesions in 120 patients with breast nodules, including 92 benign nodules and 28 malignant nodules. The results of BI-RADS-US classification showed that there were 85 benign nodules and 35 malignant nodules. Emax and Eratio on different planes of malignant nodules were higher than those of benign nodules. ROC curve analysis results showed that the sensitivity and specificity of BI-MADS-US classification for diagnosing benign and malignant breast nodules were 93.00% and 87.00%, respectively. The area under the curve (AUC) of sagittal Eratio in 3D-SWE for diagnosing benign and malignant breast nodules was the largest (0.884), and the corresponding cut-off value was 3.39 kPa. The sensitivity and specificity were 86.00% and 89.00%. The AUC, sensitivity and specificity of sagittal Eratio combined with BI-RDS-US classification were 0.960, 96.00% and 96.00%, which were higher than those of single diagnosis. Conclusion 3D-SWE combined with BI-RDS-US classification can improve the diagnosis of breast nodules, reduce unnecessary surgery or needle biopsy, and avoid overtreatment.