Objective To investigate the effect of Q-switched laser treatment on skin melanin content in patients with pigmentary skin diseases. Methods A total of 100 patients with pigmentary skin diseases admitted to the Department of Dermatology, Wenshang County Dermatology Prevention and Control Center from May 2023 to May 2024 were selected as the research subjects, and they were divided into the control group and the experimental group by the random number table method, with 50 patients in each group. The control group received traditional drug treatment, and the experimental group received Q-switched laser treatment. The skin melanin content, treatment effect, treatment satisfaction and recurrence were compared between the two groups. Results The skin melanin content in the experimental group at 1 and 3 months after treatment was lower than that in the control group (P <0.05). The total effective rate in the experimental group (96.00%) was higher than that in the control group (76.00%) (P <0.05). The treatment satisfaction in the experimental group (98.00%) was higher than that in the control group (70.00%) (P <0.05). The recurrence rates of the experimental group at 1, 3, and 6 months after treatment were lower than those of the control group (P <0.05). Conclusion Q-switched laser treatment has a good effect in patients with pigmentary skin diseases. It can effectively reduce skin melanin content, optimize skin condition, and reduce the incidence of adverse reactions and recurrence rate, which is conducive to improving treatment satisfaction. It is a safe and effective treatment protocol.