Objective To explore the effect of poly-L-lactic acid (PLLA) bidirectional barbed thread combined with botulinum toxin type A (BTX-A) injection on skin condition in patients undergoing facial rejuvenation. Methods A total of 84 patients who underwent facial rejuvenation treatment in Chengdu Hi-Tech Shengzhiyu Medical Beauty Clinic from May 2024 to December 2025 were selected as the research subjects, and they were divided into the control group and the study group by the random number table method, with 42 patients in each group. The control group was treated with BTX-A injection, and the study group was treated with PLLA bidirectional barbed thread combined with BTX-A injection. The facial laxity, wrinkle improvement, skin condition and adverse reaction rate were compared between the two groups. Results At 3 months after operation, the ABC radian and distance from pupil point to nasolabial fold and point C of the study group were lower than those of the control group (P<0.05). At 3 months after operation, the scores of FWS and WSRS in the study group were lower than those in the control group (P<0.05). At 3 months after operation, the scores of skin moisture and elasticity in the study group were higher than those in the control group, while the scores of sebum and pigment spot were lower than those in the control group (P<0.05). There was no statistically signiffcant difference in the incidence of adverse reactions between the two groups (P>0.05). Conclusion The combined application of PLLA bidirectional barbed thread and BTX-A injection in patients undergoing facial rejuvenation can relieve skin laxity and wrinkles, and optimize overall skin condition, with low risk of adverse reactions.