Objective To investigate the effect of microneedle introduction of collagen combined with tranexamic acid on skin lesions in patients with melasma. Methods A total of 80 patients with melasma admitted to Wuxi Liangxi Yuemeiren Medical Beauty Clinic from January 2022 to December 2024 were selected as the research subjects. According to the random number table method, they were divided into the reference group (n =40) and the experimental group (n =40). The reference group was treated with conventional microneedle injection of tranexamic acid, and the experimental group was treated with microneedle introduction of collagen combined with tranexamic acid. The skin lesions, Melasma Area and Severity Index (MASI) score and facial image parameters were compared between the two groups. Results After treatment, the skin lesion score of the experimental group [(1.16±0.07)scores] was lower than that of the reference group [(1.78±0.14)scores] (P <0.05). The MASI scores of the experimental group after 3 and 6 times of treatment were lower than those of the reference group (P <0.05). After treatment, the a*, b* values, brown spot percentage and colour spot percentage in the experimental group were lower than those in the reference group, and the L* value was higher than that in the reference group (P <0.05). There was no significant difference in the red area percentage between the two groups after treatment (P >0.05). Conclusion Microneedle introduction of collagen combined with tranexamic acid in the treatment of melasma can effectively lighten colour spots, improve skin lesions, repair the skin barrier, and has good safety.