Objective To explore the effect of traditional Chinese medicine internal regulation combined with external treatment on skin physiological parameters in patients with melasma. Methods A total of 50 patients with melasma admitted to the Outpatient Department of Liangxi District Qingmingqiao Street Community Health Service Center from March 2021 to September 2023 were selected, and they were divided into the control group and the observation group by the random number table method, with 25 patients in each group. The control group was given conventional western medicine, and the observation group was given traditional Chinese medicine internal regulation combined with external treatment. The clinical efficacy, skin physiological parameters, adverse reaction rate and recurrence were compared between the two groups. Results The total effective rate of the observation group (88.00%) was higher than that of the control group (68.00%) (P<0.05). After treatment, the TEWL of the observation group was lower than that of the control group, and the WCSC was higher than that of the control group (P<0.05). The incidence of adverse reactions in the observation group (24.00%) was lower than that in the control group (88.00%) (P<0.05). The recurrence rate and the increase range of MASI score in the observation group were lower than those in the control group (P<0.05). Conclusion Traditional Chinese medicine internal regulation combined with external treatment has a good effect in improving the clinical symptoms of patients with melasma, which can effectively optimize skin physiological parameters, with fewer adverse reactions, low recurrence rate, good overall safety and long-lasting curative effect.