Objective To investigate the feasibility, safety, and clinical value of endoscopic-assisted skin-sparing mastectomy combined with immediate implant-based breast reconstruction performed as day surgery for breast cancer, aiming to provide a reference for major hospitals seeking to implement a day surgery model for breast cancer treatment. Methods We retrospectively analyzed the patients who underwent endoscopic-assisted skin-sparing mastectomy combined with immediate implant-based breast reconstruction for breast cancer at West China Hospital of Sichuan University from June 2021 to December 2022, and they were divided into a day surgery group and a conventional inpatient group based on their admission model. The operative indicators, Breast-Q scores, preoperative waiting time, length of hospital stay, hospitalization costs and complications of the two groups were analyzed. Results Except for intraoperative bleeding (P=0.007), the difference between the two groups in comparison of the rest of the operative indicators was not statistically significant (all P>0.05); there was no significant difference between the two groups in preoperative and postoperative Breast-Q scores (all P>0.05); the preoperative waiting time and length of stay in hospital of the day surgery group were 4.0 (3.0, 11.0) days and 1.0 (1.0, 1.0) days, respectively, which were significantly shorter than that of the conventional inpatient group; the postoperative pain score in the day surgery group [1.0 (1.0, 1.0) points] was lower than that in the conventional inpatient group [3.0 (3.0, 3.0) points], with a statistically significant difference between the two groups (P<0.001). Additionally, the total hospitalization costs for the day surgery group and conventional inpatient group were 50 656.5 (48 145.3, 62 597.3) RMB and 53 689.3 (50 469.1, 64 826.5) RMB, respectively.The total hospitalization cost in the day surgery group was significantly lower than that in the conventional inpatient group, with a statistically significant difference between the two groups (P=0.001). There was no statistically significant difference in complications between the two groups (all P>0.05). Conclusion Endoscopic-assisted skin-sparing mastectomy combined with immediate implant-based breast reconstruction in day surgery is feasible and safe. Without increasing postoperative complications, it effectively reduces hospitalization costs and shortens medical care time, demonstrating significant clinical value.