Objective To investigate the effect of Botulinum Toxin Type A (BTX-A) injection combined with cross-linked hyaluronic acid (CL-HA) fflling on facial contour symmetry in patients with midface aging. Methods A total of 60 patients with midface aging treated in Nanjing Xuanwu Yestar Medical Aesthetic Clinic from March 2023 to March 2025 were selected, and they were divided into the control group and the observation group according to different treatment regimens, with 30 patients in each group. The control group received simple CL-HA fflling, and the observation group received BTX-A injection combined with CL-HA fflling. The facial aesthetic contour symmetry, FACE-Q appearance satisfaction scores, skin physiological parameters and treatment satisfaction were compared between the two groups. Results At 3 months after treatment, the OCDD, MHD and NFDD values in the observation group were lower than those in the control group, and the scores of SFAO, SFSQ and PF were higher than those in the control group (P<0.05). At 3 months after treatment, the R2 value and stratum corneum hydration in the observation group were higher than those in the control group, while the TEWL was lower than that in the control group (P<0.05). The treatment satisfaction rate of the observation group (96.67%) was higher than that of the control group (76.67%) (P<0.05). Conclusion BTX-A injection combined with CL-HA fflling can improve facial contour symmetry of patients with midface aging, elevate FACE-Q appearance satisfaction and treatment satisfaction.