Ultrasonography is the most commonly used method to evaluate the status of axillary lymph node metastasis (ALNM) in breast cancer. It can be used to predict axillary lymph node status by conventional two-dimensional gray-scale, blood flow, elastography and contrast-enhanced ultrasound according to the morphology, long- to-short axis ratio, cortical thickening, hilum status, blood flow and other indicators. However, the positive rate and accuracy of ultrasonographic techniques are not satisfactory due to many factors including the size and position of axillary lymph nodes, axillary depth, experience of physicians and different resolution of ultrasonographic instrument. Therefore, how to improve the efficacy of the evaluation of axillary lymph node metastasis in breast cancer has become an urgent problem.