Objecitve To ivestigate the ultrasonographic features of pure mucinous carcinoma of the breast (PMBC). Methods 27 lesions of PMBC were selected to analyze the clinic, pathologiacal and ultrasonographic features. To compare the differences in ultrasound scores and blood flow scores between patients of conventional pure mucinous breast carcinoma without micropapillary architecture (cPMBC) and mutinous carcinomas with micropapillary pattern (MUMPC).And to compare the differences in ultrasound scores of PMBC with and without lymph node metastasis, with different TMN stages and molecular types. SPSS23.0 software was used for data analysis. Results 27 PMBCs were categorized into 20 cPMBCs and 7 MUMPCs. Most of PMBCs showed hypoechoic with large leaf or angular protrusion, rare of calcification and liquefied. Median of ultrasound scores and blood flow scores were was 1 points. There were no differences in ultrasound scores and blood flow scores between cPMBCs and MUMPCs(all P＞0.05), and no differences in ultrasound scores between the PMBCs with and without lymph node metastasis, with different TMN stages and molecular types (all P＞0.05). Conclusion The ultrasound characteristics of PMBC are not typical,we should pay more attention to the lesions with leaf or angular protrusion while accompanied by calcification or liquefied component for reducing Misdiagnosis.