Abstract: Objective To investigate the application value of superb microvascular imaging （SMI）, real-time tissue ultrasound elastography （RTE）, and conventional high-frequency color Doppler ultrasound （US） in differentiating malignant from benign American College of Radiology（ACR）Breast Imaging Reporting and Data System（BI-RADS）category 4 nodular breast lesions. Methods A total of 300 patients with 325 ACR BI-RADS category 4 breast nodules were included. Multimodal ultrasound including US, SMI and RTE were performed before surgery. The sensitivity, specificity, accuracy, positive predictive value （PPV）, negative predictive value （NPV） and diagnostic efficiency of multimodal ultrasound were compared with pathological result. Results In differentiating malignant from benign ACR BI-RADS category 4 nodular breast lesions, the sensitivity, specificity, accuracy, PPV and NPV of US were 75.41%, 72.41%, 73.54%, 62.16% and 83.05%, respectively; those of SMI were 86.01%, 88.67%, 87.69%, 82.03% and 91.37%; those of RTE were 87.70%, 89.16%, 88.62%, 82.31% and 92.35% respectively; and those of multimodal ultrasound combined diagnosis were 95.08%, 93.10%, 93.85%, 91.34% and 95.45%, respectively. The area under receiver operating characteristic curve （AUC） was 73.9%、88.6%、90.5% and 97.0% for US, SMI, RTE and multimodal ultrasound imaging in the differential diagnosis of ACR BI-RADS category 4 nodular breast lesions. Conclusions Multimodal ultrasound imaging can compensate the disadvantages of single imaging technology, especially conventional US, in differentiating malignant from benign ACRBI-RADS category 4 nodular breast lesions, and provide more comprehensive diagnostic information of nodules, and significantly improve the diagnostic efficiency of ACR BI-RADS category 4 breast nodules which were difficult to identify from malignant to benign lesions.