Abstract: Objective To explore the influence of biological characteristics of breast cancer in mammography on surgical margin status of breast-conserving surgery. Methods One hundred and twenty patients diagnosed with stage Ⅰ or Ⅱ primary breast cancer received breast-conserving surgery were enrolled in this study. According to the mammography images， the breast cancer patients were divided into five groups， including masses type group， mass associated with calcification type group， calcification type group， asymmetries type group and architectural distortion type group. Total excision of breast lumps and surrounding tissue were performed about 1 cm. Intraoperative rapid pathological was employed to determine the initical state of cutting edge， which was confirmed by paraffin pathology. The relationship between biological characteristics of breast cancer in mammography and surgical margin status was analyzed. Results Pathologic features including age， tumor size， grade， nodal metastases， estrogen receptor status， progesterone receptor status and HER-2 expression were not associated with margin status of breast cancer patients. The positive rate of patients with tumor thrombus in vascular was 26.3％ （5／19）， higher than 6.9％ （7／101） of patients without tumor thrombus in vascular with statistical significance （P＜0.05）. No statistically significant difference was observed on the initial surgical margin status among five groups according to mammography classification. As for isolated malignant carcinoma， surgical margin status was not correlated with imaging characteristics of the tumor. However， mixed malignant carcinoma was significantly correlated with the margin status （P=0.005）. Conclusion For breast-conserving surgery， we may need to consider characteristics of the tumor mammography classification and estimate pathological type in order to reduce the probability of positive margin.