Abstract: Objective To investigate the ultrasonographic and pathological features of phyllodes tumor of breast. Methods A total of 51 patients with phyllodes tumor of breast diagnosed by pathology in our hospital from June 2018 to April 2020 were selected as the research objects, and the general materials such as unilateral single tumor location, pathological grading, tumor size, axillary lymph node metastasis were collected. According to the pathological grading, the patients were divided into benign group, borderline group and malignant group, and the differences of ultrasonic characteristics were compared among the three groups. Results Out of 51 cases with phyllodes tumor of breast, 33 cases(64.7%)were benign, 13 cases(25.5%)were borderline, and 5 cases(9.8%)were malignant. The minimum tumor volume was 7.6 mm×3.6 mm×6.7 mm, and the maximum tumor volume was 168 mm×135 mm×120 mm. No case was found axillary lymph node metastasis. The sonographic appearance of the breast phyllode tumor presented as solid or cystic solid lesions, among which oval-shaped tumor accounted for 13.7%, lobulation-shaped for 86.3%, clear boundary for 58.8%, - local ambiguity or ambiguity for 41.2%, smooth and neat edges for 54.9%, rough edges for 45.1%, homogeneity of internal echo for 33.3%, and heterogeneity for 66.7%. Besides, tumor with blood flow signal level of 0 to I accounted for 31.4%, level of Ⅱ to Ⅲ for 68.6%, resistance index(RI)<0.7 for 66.7%, and RI >0.7 for 33.3%. The morphology of lobar tumors and blood flow grading in the benign group, the borderline group and the malignant group showed no significant differences(P>0.05). Lesion boundary, edge, internal echo and blood flow RI among the three groups showed significant differences(P<0.05). The results showed that the tumor had the characteristics of local unclear or fuzzy boundary, rough edges, heterogeneity of internal echo, patchy irregular anechoic region in varying degrees. The malignant group and the borderline group had significantly higher ratio of patients with blood flow RI>0.7 than that of the benign group(P<0.05). Conclusion Different pathological types of breast phyllodes tumors have different characteristics, and tumor boundary, edge, internal echo and blood flow RI show certain reference values in judging benign and malignant types of tumors.