Objective To investigate the effect of 755 nm picosecond laser combined with nano-microneedle introduction of glutathione on skin barrier function in patients with melasma. Methods A total of 80 patients with melasma treated in Nanjing Arsmo Qizhi Aesthetic Hospital from January 2022 to August 2025 were selected, and they were divided into the control group and the observation group according to different treatment schemes, with 40 patients in each group. The control group was treated with 755 nm picosecond laser, and the observation group was treated with 755 nm picosecond laser combined with nano-microneedle introduction of glutathione. The modified Melasma Area and Severity Index (mMASI) score, skin barrier function, treatment effect and adverse reaction rate were compared between the two groups. Results After treatment, the mMASI score of the observation group was lower than that of the control group (P <0.05). After treatment, the stratum corneum hydration and sebum content in the observation group were higher than those in the control group, and the TEWL and skin pH value were lower than those in the control group (P <0.05). The total effective rate of the observation group (92.50%) was higher than that of the control group (75.00%) (P <0.05). There was no statistically significant difference in the incidence of adverse reactions between the two groups (P >0.05). Conclusion 755 nm picosecond laser combined with nano-microneedle introduction of glutathione is effective in the treatmentof melasma. It can promote the repair of skin barrier function, reduce the severity of melasma, and does not increase the risk of adverse reactions, showing good application safety.