Objective To analyze the shaping effect of autologous fat grafting breast augmentation and implant-based breast augmentation in patients with mild breast ptosis. Methods A total of 60 patients with mild breast ptosis admitted to the Department of Plastic Surgery, Guangzhou Rosely Medical Aesthetics Hospital from March 2023 to March 2024 were selected as the research subjects, and they were divided into the control group and the observation group by the random number table method, with 30 patients in each group. The control group was treated with implant-based breast augmentation, and the observation group was treated with autologous fat grafting breast augmentation. The maximal inspiratory chest circumference increase at nipple level, complications and satisfaction with shaping effect were compared between the two groups. Results The maximal inspiratory chest circumference increase at nipple level in the observation group at 6 and 12 months after operation was higher than that in the control group (P <0.05). The incidence of complications in the observation group (3.33%) was lower than that in the control group (20.00%) (P <0.05). The satisfaction with shaping effect in the observation group (100.00%) was higher than that in the control group (80.00%) (P <0.05). Conclusion Compared with implant-based breast augmentation, autologous fat grafting in the treatment of mild breast ptosis can effectively increase the maximal inspiratory chest circumference at nipple level, reduce the incidence of complications, and thus improve patients' satisfaction with shaping effect.