Objective: To investigate the clinical effect of externally applied traditional Chinese medicine (TCM) masks on skin tone uniformity and skin barrier function in patients with melasma. Methods: Clinical data of 70 melasma patients admitted from January 2023 to January 2025 were retrospectively analyzed. According to different treatment plans, patients were divided into a control group and an observation group, with 35 cases in each. The control group received conventional whitening and spot-removal care, while the observation group was treated with external TCM masks in addition to the control group's regimen. Skin barrier function indicators, skin tone uniformity parameters, melasma lesion area and severity index, and skin physiological indicators were compared between the two groups. Results: After treatment, transepidermal water loss in the observation group (12.35±2.18 g/(m2·h)) was lower than that in the control group (16.72±2.86 g/(m2·h)), and stratum corneum hydration (48.62±5.37%) was higher than in the control group (41.28±4.95%) (P<0.05); the observation group had higher skin brightness (65.83±4.26) than the control group (58.94±4.51), and lower yellowness (16.24±2.13) and redness (8.42±1.35) compared to the control group (19.87±2.68 and 11.26±1.72, respectively) (P<0.05); melasma lesion area and severity index score in the observation group (8.42±2.15) were lower than in the control group (12.86±2.73) (P<0.05); sebum production (118.52±15.73 μg/cm2) and skin elasticity coefficient (0.72±0.08) in the observation group were superior to the control group (P<0.05). Conclusion: External application of TCM masks can effectively improve skin barrier function, enhance skin tone uniformity, reduce melasma severity, and optimize skin physiological state in melasma patients, demonstrating considerable clinical value.