Objective：To retrospectively analyze the ultrasound features of primary breast tumors and axillary lymph nodes in patients with lateral quadrant breast cancer，and to construct a nomogram model to provide imaging evidence for better clinical assessment of axillary lymph node metastasis in these patients. Methods：We retrospectively analyzed ultrasonographic features of theaxillary lymph nodes and primary breast tumors in 127 patients with lateral quadrant breast cancer，confirmed by pathology at Xishan People’s Hospital of Wuxi City. Patients with axillary lymph node metastasis were categorized into the positive group（54 cases），while those without axillary lymph node metastasis were classified into the negative group（73 cases）. Univariate and multivariate logistic regression analyses were performed to identify therisk factors for lymph node metastasis. The dataset was randomly divided into a training set and a validation set using the R language. A nomogram prediction model was constructed based on the training set to predict the risk of axillary lymph node metastasis and validated in the validation set. Diagnostic performance was evaluated using receiver operating characteristic（ROC）curves，while calibration curves and the Hosmer-Lemeshow test were used to assess the consistency between thepredicted and actual values of the nomogram. Results：Tumor spiculated margin（OR=4.16，95% CI：1.25-13.79）and unclear lymphatic gate structure（OR=19.20，95% CI：1.98-186.36）were identified as independent risk factors of axillary lymph node metastasis in patients with lateral quadrant breast cancer. Furthermore，a nomogram model was developed to predict axillary lymph node metastasis in lateral quadrant breast cancer cases. The ROC curves howed that the area under the curve （AUC）for the training set was 0.74（95%CI：0.62-0.86）and the AUC for the validation set was 0.73（95%CI：0.62-0.84）. Hosmer-Lemeshow test results indicated no significant deviation from goodness-of-fit for both the training set and validation set with P-values of 0.570 and 0.552，respectively. Conclusion：Ultrasound plays a valuable role in the assessment of axillary lymph node metastasis in patients with lateral quadrant breast cancer. The nomogram prediction model based on logistic regression demonstrates good safety， reliability，and practicality for clinical use.