Objective: To explore the application of the downward flap patch technique in single-port axillary endoscopic breast reconstruction with implants. Methods: A retrospective analysis was conducted on the clinical data of patients who underwent single-port axillary endoscopic breast cancer radical resection with implant-based reconstruction at the Department of Oncology Surgery, Ningxia Medical University General Hospital from August 2020 to March 2023. The patients’ postoperative drainage volume, early complications, and breast reconstruction satisfaction were analyzed using the BREAST-Q questionnaire. Results: The average total drainage volume was 235 ml on the second day after surgery. A total of 8 patients (15.38%) experienced complications, including 7 cases of incision infection, 5 cases of incision dehiscence, and 2 cases of flap necrosis. There were also 2 cases of local flap ischemic necrosis. Seven patients had wound infections, including 3 cases of simple infection, 2 cases of flap necrosis, and 2 cases of combined incision dehiscence. All 52 patients completed the 3-month follow-up without any loss to follow-up. During the follow-up period, no adverse events such as recurrence, metastasis, or death occurred in any of the patients. The BREAST-Q scores of patients who experienced complications were significantly lower than those who did not. Patients with higher postoperative drainage volumes were more likely to develop wound infections. The incidence of flap necrosis and incision dehiscence was not related to postoperative compression dressing or TNM staging, while the incidence of wound infection was related to compression dressing and regional lymph node metastasis. The breast reconstruction satisfaction score was not related to TNM staging. Conclusion: Single-port axillary endoscopic breast cancer radical resection with implant-based reconstruction achieved good results in breast cancer treatment and shaping. The downward flap patch technique is simple to operate, has good implant coverage, and can achieve good breast reconstruction satisfaction.