BACKGROUND Plasma cell mastitis (PCM), a common type of mastitis often mimics malignancy clinically and radiologically. OBJECTIVE The study was designed to explore the diagnostic value of superb microvascular imaging (SMI) in differentiating PCM from malignant breast lesions. METHODS A total of 95 breast lesions underwent conventional ultrasound (US) and SMI examination between May 2016 and April 2018. Vessels were detected in SMI in a quantitative manner. Blood flow parameters including systolic peak velocity (SPV), resistance index (RI), and pulsatility index (PI) were evaluated. We further assessed the diagnostic performances of US and US+SMI. RESULTS The majority of PCM were in regular shape and displayed no calcification compared with malignant breast lesions. Regarding blood flow parameters, PCM obtained significantly lower mean value of RI and PI compared with malignant lesions (P < 0.05). The sensitivity, specificity and accuracy rate of US+SMI (84.62%, 76.47%, 83.16%) was significantly higher than those of US (78.21%, 64.71%, 75.59%). CONCLUSIONS The present study supports that SMI is a novel ultrasound technology in revealing micro-vessels in breast lesions. The combined modality of US+SMI presented a better diagnostic performance in making a distinction between PCM and malignant breast carcinomas.