Objective:Combined ultrasound and axillary metastatic clipped lymph nodes was developed a model to predict the pathological complete response(pCR)of axillary lymph nodes in clinically lymph node - positive(cN +)breast cancer patients after neoadjuvant systemic therapy(NST). Methods:Eighty-eight patients were randomly assigned to the testing or validation set at a ratio of 7∶3. Before NST,the lymph nodes most suspicious on ultrasound images and confirmed as metastatic by pathological biopsy were selected and marked with a titanium clip under ultrasound guidance. Univariate and multivariate logistic regression analyses of the testing set were performed. A risk score model was developed based on the results of multivariate analysis. Results:The axillary pCR rate was 48%(42/88). Hormone receptor status,N grade and changes in the number of abnormal lymph nodes were determined by ultrasonography,and changes in cortical thickness of the clipped lymph nodes were identified as independent factors and established the risk score model. In the score range of-13 to-9 and 1 to 10,the axillary pCR rate of the testing set was 100% and 0% , respectively. The area under the receiver operating characteristic curves of the testing and validation sets were 0.931(95% CI:0.868- 0.994)and 0.762(95% CI:0.576-0.947),respectively. Conclusion:The risk score model based on ultrasound and clipped lymph nodes accurately predicte the axillary lymph node status of breast cancer patients with cN + after NST. When the risk score was between -13 and -9,the false-negative rate of axillary lymph node metastasis was 0%,allowing these patients to avoid axillary lymph node dissection and a series of complications.