Objective To explore the effect of precise dosage and layer control of hyaluronic acid in cosmetic injection on facial rejuvenation. Methods A total of 92 patients who received facial rejuvenation treatment in Guangzhou Yestar Medical Beauty Hospital from January to December 2024 were selected as the research subjects. According to the random number table method, they were divided into the control group and the study group, with 46 patients in each group. The control group was treated with collagen filling injection, and the study group was treated with precise dosage and layer control of hyaluronic acid. The skin barrier function, skin status, facial contour parameters, cosmetic effect and complications were compared between the two groups. Results The the transepidermal water loss of the study group after treatment was lower than that of the control group, and the skin stratum corneum hydration was higher than that of the control group (P<0.05). After treatment, the scores of moisture and elasticity in the study group were higher than those in the control group, and the scores of dark spot and sebum were lower than those in the control group (P <0.05). After treatment, the lower facial length of the study group was longer than that of the control group, and the lower facial width was shorter than that of the control group (P <0.05). The total effective rate of cosmetic effect in the study group (97.83%) was higher than that in the control group (82.61%) (P <0.05). The incidence of complications in the study group (4.35%) was lower than that in the control group (21.74%) (P <0.05). Conclusion The precise dosage and layer control of hyaluronic acid in cosmetic injection has a good facial rejuvenation effect, which can improve shaping effect, skin status and durability of aesthetic effect, with a lower incidence of complications.