Background: With the continuous improvement of pathological complete response (pCR) rate after neoadjuvant therapy (NAT), it is necessary to locate the tumor bed and axillary lymph nodes (ALNs) for subsequent surgery. Therefore, breast tissue markers emerge. This study aims to evaluate the feasibility and accuracy of ultrasound (US)-guided placement of markers for locating ALNs of breast cancer. Methods: A total of 285 patients who received US-guided placement of markers for locating ALNs in our hospital were selected. Among these patients, 87 patients were in the early breast cancer (EBC) group with negative ALNs and 198 ones were in the NAT group with positive ALNs. Data including the basic information of patients, position and size of ALN, process of US-guided marker placement, placement success rate, complications, detection rate of marker by imaging, and shift rate were recorded. Results: All patients were successfully underwent US-guided marker placement. And the average operation time was 2 minutes with no adverse reactions. All the patients underwent surgery successfully. US, computer tomography (CT) and magnetic resonance imaging (MRI) were used to detect the marker. The detection rate of markers by US and CT/MRI were 100% (87/87) in EBC group, and 98.5% (195/198) and 100% (198/198) by US and CT/MRI, respectively, in NAT group. The postoperative marker shift rate was 2.1% (6/285), including 3.4% (3/87) marker shift rate in EBC group and 1.5% (3/198) in NAT group, with no statistically significant difference between them. Conclusions: US-guided marker placement in ALNs of breast cancer is simple and safe, with firm positioning and low shift rate, which is convenient for clinical promotion.