Objective To investigate the cosmetic effect of botulinum toxin combined with fat filling in facial rejuvenation surgery. Methods From June 2021 to June 2022, 52 patients who were going to receive facial shaping in Cangzhou Meiyimei Medical Beauty Clinic were selected as the research objects and randomly divided into control group and observation group, with 26 patients in each group. The control group was treated with botulinum toxin, and the observation group was treated with botulinum toxin combined with fat filling. The clinical efficacy, facial contour parameters, skin conditions and complications were compared between the two groups. Results The total effective rate of treatment in the observation group was 92.31%, which was higher than 65.38% in the control group, and the difference was statistically significant (P <0.05). After treatment, the length and width of the lower part of the surface in the observation group were better than those in the control group, and the differences were statistically significant (P <0.05). After treatment, the scores of dark spot, moist and elasticity in the observation group were better than those in the control group, and the differences were statistically significant (P <0.05). The incidence of complications in the observation group was 19.23%, which was lower than 26.92% in the control group, and the difference was statistically significant (P <0.05). Conclusion Botulinum toxin combined with fat filling can improve the facial rejuvenation effect, improve the skin contour and skin quality, and reduce the incidence of complications, which is worthy of clinical application.