Objective To explore the effect of poly-L-lactic acid combined with type A botulinum toxin injection in facial contour remodeling. Methods A total of 60 patients who underwent facial contour remodeling in Hangzhou Chunshang Medical Beauty Clinic Co., Ltd. from February to June 2025 were selected as the research subjects, and they were divided into the control group (n =30) and the observation group (n =30) by the random number table method. The control group was treated with type A botulinum toxin injection alone, and the observation group was treated with poly-L-lactic acid combined with type A botulinum toxin injection. The clinical efficacy, lower facial contour indicators, pain degree, satisfaction and adverse reaction rate were compared between the two groups. Results The total effective rate of the observation group (93.33%) was higher than that of the control group (70.00%) (P<0.05). There were no statistically significant differences in WLF, LIF, WLF/LIF and total facial length between the two groups after operation (P>0.05). The ∠AOB of the observation group after operation was better than that of the control group (P<0.05). The VAS score of the observation group was lower than that of the control group, and the satisfaction score was higher than that of the control group (P<0.05). There was no statistically significant difference in the incidence of adverse reactions between the two groups (P>0.05). Conclusion The application of poly-L-lactic acid combined with type A botulinum toxin injection in facial contour remodeling has a definite effect. It can effectively improve the lower facial contour indicators, cause mild pain during the operation, achieve high patient satisfaction, and the incidence of adverse reactions was not increased after operation, which is worthy of clinical application.