Abstract： Objective:To evaluate the changes of axillary lymph nodes after neoadjuvant chemotherapy (NAC) for breast cancer, and to explore the value of magnetic resonance imaging (MRI) in evaluating the efficacy of NAC.Methods:All patients with breast cancer who received NAC, post NAC MRI and axillary surgery were reviewed. The imaging findings, axillary operation methods and postoperative histopathological findings were analyzed.Results:Among 166 patients treated with NAC, 58 patients underwent MRI after neoadjuvant chemotherapy before surgery and were included in the analysis. The average age of the patients was 45 years. MRI results of 39 patients with NAC showed that the status of axillary lymph nodes (ALN) was normal, of which 32 cases underwent sentinel lymph node biopsy (SLNB) and 7 cases underwent axillary lymph node dissection (ALND). 28 of the 39 cases were negative in the final pathological examination, so the negative predictive value was 71.8%. Of the 19 patients with abnormal ALN status after NAC, 10 cases were positive for metastasis in the final pathological examination, and the positive predictive value was 52.6%. Among 166 patients receiving NAC treatment, 58 patients received MRI examination after neoadjuvant chemotherapy before surgery and were included in the analysis. The average age of the patient was 45 years old. After NAC treatment, MRI results of 39 patients showed that the axillary lymph nodes (ALN) were in normal condition. Among them, 32 patients received sentinel lymph node biopsy (SLNB), and 7 patients received axillary lymph node dissection (ALND) directly. 28 of the 39 cases had negative metastasis in the final pathological examination, so the negative predictive value was 71.8%. In 19 patients with abnormal ALN status after NAC, 10 of them were positive for metastasis in the final pathological examination, with a positive predictive value of 52.6%.Conclusion:The evaluation of MRI axillary imaging results after NAC shows that the accuracy of MRI axillary imaging results after NAC in predicting negative lymph node lesions is higher than that of positive lymph node lesions. Breast MRI evaluation has certain diagnostic and evaluation value for the selection of axillary surgery in patients after NAC.