Objective To analyze the effect of long pulse width 1064 nm Nd:YAG laser in the treatment of chloasma. Methods A total of 40 patients with chloasma admitted to our hospital from January to December 2022 were selected as the research objects. They were divided into experimental group and reference group by random number table method, with 20 patients in each group. The reference group was treated with L-vitamin C introduction, and the experimental group was treated with L-vitamin C introduction immediately after long pulse width 1064 nm Nd:YAG laser treatment. The clinical efficacy and complication rate of the two groups were compared. Results The total effective rate of treatment in the experimental group was 100.00%, which was higher than 55.00% in the reference group, the difference was statistically significant (P <0.05). The incidence of complications in the experimental group was 15.00%, which was lower than 45.00% in the reference group, the difference was statistically significant (P <0.05). Conclusion Long pulse width 1064 nm Nd:YAG laser treatment for patients with chloasma can improve the therapeutic effect and reduce the incidence of complications.