Objective To analyze the effect of modified Danggui Shaoyao decoction combined with traditional Chinese medicine mask on TCM syndrome scores and skin barrier function in patients with melasma. Methods A total of 85 patients with melasma admitted to Nanjing Jiayi Medical Beauty Clinic from June 2023 to December 2025 were selected as the research subjects. According to the random number table method, they were divided into the control group (n =42) and the observation group (n =43). The control group was treated with traditional Chinese medicine mask, and the observation group was treated with modified Danggui Shaoyao decoction combined with traditional Chinese medicine mask. The TCM syndrome scores, skin barrier function and serum oxidative stress indicators were compared between the two groups. Results After treatment, the scores of patch, skin lesion and skin sensitivity in the observation group were lower than those in the control group (P <0.05). After treatment, the sebum content and stratum corneum hydration in the observation group were higher than those in the control group, and the transepidermal water loss was lower than that in the control group (P <0.05). After treatment, the levels of GSH-Px and SOD in the observation group were higher than those in the control group, and the MDA level was lower than that in the control group (P <0.05). Conclusion Modified Danggui Shaoyao decoction combined with traditional Chinese medicine mask has definite treatment effect on patients with melasma. It can effectively improve TCM syndromes, strengthen skin barrier function, and help to optimize serum oxidative stress indicators, which is worthy of clinical promotion.