Objective: To explore the value of the diagnostic performance of scoring by shear wave elastography (SWE) combined with contrast-enhanced ultrasound (CEUS) with respect to differentiating benign and malignant in BI-RADS 4 breast nodules with different sizes. Methods: From August 2020 to October 2021, a total of 167 BI-RADS 4 breast nodules in 158 patients were collected from the First Hospital of Shanxi Medical University were divided into large size group (＞20 mm) and small size group (≤20 mm), Both SWE and CEUS were performed, SWE and CEUS scoring alone and combined scoring were built in each nodule. The pathological finings were utilized as the gold standard, receiving operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of the separate scoring and combined scoring for discrimination between benign and malignant breast lesions. Results: In large size group, area under the ROC curve(AUC) of SWE/CEUS scoring alone was was 0.786/0.820, and the diagnostic sensitivity, specificity, accuracy, positive predictive value (PPV) and Negative predictive value (NPV) were 79.5%/81.8%, 68.7%/75.0%, 76.3%/78.9%,79.5%/81.8% and 71.9%/75.0%, respectively; There was no significant difference between the SWE alone score and the CEUS alone score (Z=0.537, P>0.05). when the cut-off value of combined scoring was 6.5 points, the AUC was 0.885, 95% confidence interval (CI) was 0.791 to 0.947, and the sensitivity, specificity, accuracy, PPV and NPV were 88.6%, 87.5%, 88.2%, 88.6% and 84.8%, respectively, which were higher than scoring alone, and the differences had statistical significance (Z=2.153/2.287, P<0.05) . In small size group, the AUC of SWE/CEUS scoring alone was 0.730/0.778, and the diagnostic sensitivity, specificity, accuracy, PPV and NPV were 61.0%/70.7%, 68.0%/70.0%, 64.8%/69.2%, 61.0%/65.1% and 68.0%/72.9%, respectively; There was no significant difference between the SWE alone score and the CEUS alone score (Z=0.688, P>0.05). when cut-off value of the combined scoring was 5.5 points, the AUC was 0.868, 95% CI was 0.781 to 0.930, and the diagnostic sensitivity, specificity, accuracy, PPV and NPV were 87.8%, 84.0%, 86.8%, 83.7% and 89.6%, respectively, which were higher than scoring alone, and the differences had statistical significance (Z=3.040/2.746, P<0.05). Conclusion: Scoring by SWE combined with CEUS has a high diagnostic value for differentiating benign from malignant BI-RADS 4 breast nodules of different sizes, especially for small nodules, which the diagnostic cut-off point should be appropriately reduced, can effectively reduce unnecessary preoperative biopsies to some extent and improve diagnostic accuracy.