Objective To analyze the clinical effect of autologous fat transplantation assisted by adipose-derived stem cells augmentation in the treatment of micromastia. Methods A total of 68 patients with micromastia admitted to our hospital from July 2020 to July 2023 were selected as the research objects. They were divided into control group and observation group by random number table method, with 34 patients in each group. The control group was treated with simple autologous fat transplantation for augmentation mammaplasty, and the observation group was treated with autologous fat transplantation assisted by adipose-derived stem cells for augmentation mammaplasty. The improvement effect of breast volume, three-dimensional added value, uplift value and maintenance rate of postoperative uplift increased were compared between the two groups. Results The total effective rate of breast volume improvement in the observation group was 97.06%, which was higher than 76.47% in the control group (P <0.05). The increased values of CC, SN-N, C-N and N-MF in the observation group were higher than those in the control group at 3 months after operation (P <0.05). The uplift value of the observation group was higher than that of the control group at 1 and 3 months after operation (P <0.05). The maintenance rate of uplift increased in the observation group was higher than that in the control group at 1 and 3 months after operation (P <0.05). Conclusion Autologous fat transplantation assisted by adipose-derived stem cells augmentation has high application value for patients with micromastia. It can better improve the breast shape and has a good postoperative maintenance effect, which is worthy of clinical application.