Objective To analyze the effect of fat granule injection transplantation on facial volume recovery rate and fat survival rate in patients with facial soft tissue defect. Methods A total of 64 patients with facial soft tissue defect admitted to the People's Hospital of Jiawang District of Xuzhou City from June 2023 to December 2024 were selected. According to the random number table method, they were divided into the control group and the observation group, with 32 patients in each group. The control group received skin ffap transplantation, and the observation group received fat granule injection transplantation. The volume recovery rate, fat survival rate, facial aesthetic effect and complication rate were compared between the two groups. Results The volume recovery rates at 3 and 6 months after operation in the observation group were higher than those in the control group (P<0.05). The fat survival rate at 6 months after operation in the observation group was (68.97±5.63)%, which was higher than (52.74±5.58)% in the control group (P<0.05). The excellent and good rate of facial aesthetic effect in the observation group was 93.75%, which was higher than 71.88% in the control group (P<0.05). The incidence of complications in the observation group (6.25%) was lower than that in the control group (25.00%) (P<0.05). Conclusion The effect of fat granule injection transplantation in patients with facial soft tissue defect is better than that of skin ffap transplantation. It can further improve volume recovery rate and fat survival rate, optimize facial aesthetic morphology, and reduce the incidence of complications, which is worthy of clinical application.