Objective To analyze the effect of axillary incision endoscopy combined with ultrasonic scalpel in subpectoral fascia prosthetic breast augmentation. Methods A total of 80 patients undergoing prosthetic breast augmentation in the Department of Aesthetic Surgery of Nanjing Sulang Hospital Management Co., Ltd. from January 2024 to June 2025 were selected as the research subjects, and they were divided into the control group and the observation group according to different treatment methods, with 40 patients in each group. The control group underwent traditional axillary incision for subpectoral prosthetic breast augmentation, and the observation group underwent axillary incision endoscopy combined with ultrasonic scalpel for subpectoral fascia prosthetic breast augmentation. The perioperative indicators, clinical efffcacy, postoperative pain intensity, complications and satisfaction were compared between the two groups. Results The operation time, intraoperative blood loss and postoperative hospital stay in the observation group were better than those in the control group (P<0.05). The excellent and good rate of the observation group (97.50%) was higher than that of the control group (80.00%) (P<0.05). The VAS scores at 24 and 48 hours after operation in the observation group were lower than those in the control group (P<0.05). The incidence of complications in the observation group (5.00%) was lower than that in the control group (22.50%) (P<0.05). The satisfaction score of the observation group was higher than that of the control group (P<0.05). Conclusion The application of axillary incision endoscopy combined with ultrasonic scalpel in subpectoral fascia prosthetic breast augmentation can shorten operation time, reduce intraoperative blood loss, relieve postoperative pain, accelerate postoperative recovery, help to reduce the incidence of postoperative complications and improve overall patient satisfaction, which has high clinical application value.