AIM: To evaluate the effects of early versus delayed fat transplantation on post-traumatic scars using adipose-derived stem cells (ADSCs) to enhance scar quality and address the aesthetic and psychological challenges in reconstructive surgery. METHODS: This retrospective cohort study included 223 patients treated at Capital Medical University Beijing Shijitan Hospital between June 2022 and June 2023. Scar quality was evaluated using the Vancouver Scar Scale (VSS) and scar width measurements at 1, 3, and 4 months postoperatively. Complications were monitored during hospital stays and follow-up visits, while Quality of Life was assessed using the World Health Organization Quality of Life brief version (WHOQOL-BREF). RESULTS: A retrospective cohort study of 223 patients with post-traumatic scars was conducted to compare the outcomes of early (n = 108) versus delayed (n = 115) fat grafting. Scar width reduction was significantly greater in the early group at 3 months (1.19 ± 0.30 cm) and 4 months (1.97 ± 0.58 cm) compared to the delayed group (1.31 ± 0.34 cm at 3 months and 2.15 ± 0.55 cm at 4 months; p < 0.05). The early group also demonstrated better VSS scores at 3 months (6.35 ± 1.26) and 4 months (2.16 ± 0.78) than the delayed group (6.81 ± 1.48 at 3 months and 2.37 ± 0.28 at 4 months; p < 0.05). However, the early group exhibited a higher complication rate (9.26% vs. 2.61%; p = 0.034). No significant difference was found in Quality of Life scores between the two groups. CONCLUSIONS: Early fat transplantation improves scar quality but is associated with a higher complication rate.