Objective To explore the effect and the possible mechanism of alpha hydroxy acid combined with Q-switched laser in the treatment of melasma mouse model induced by UVB. Methods Totally 30 healthy female guinea pigs were selected and were randomly divided into normal group (6 guinea pigs) and model group (24 guinea pigs). The model group was given UVB combined with progesterone to induced chloasma mode. 6 model mice were randomly selected to observe the levels of both serum superoxide dismutase (SOD) and malondialdehyde (MDA) and the pathology of skin tissues by HE staining and immunohistochemistry. The normal group was handled as the same. The rest of the 18 mice in the model group were randomly divided into group A, group B and group C. Group A was treated with a combination of alpha hydroxy acid combined with Q-switched laser, group B was treated with hydroquinone, group C was done with nothing. After 4 months, the levels of SOD and MDA in serum, liver and skin lesions and the pathology of skin tissue were detected. Results Dark brown spot formed in the molding bay of model group; the expression levels of serum SOD in the model group was clearly lower, and the expression levels of serum MDA was higher than those of the normal group (P??0.05). Conclusion The curative effect of alpha hydroxy acid combined with Q-switched laser in melasma mouse model was significantly, which may be related to the exfoliation and antioxidation of alpha hydroxy acid and the selective destruction of Q-switched Laser for melanocyte.