Objective To investigate G. Pentaphyllums influence on the activity of glutathione peroxidase (GSH-PX) and catalase (CAT) in the skin of hireless photoaging mice, as well as the content of hydroxyproline (HYP). At the same time, G. Pentaphyllum's effect on the hireless photoaging mice was studied. Methods Healthy KM hireless mice were randomly divided into five groups. A skin photoaging model was established by G. Pentaphyllum administration. The changes of the activity of GSH-PX, CAT and the contents of dermal hydroxyproline in the skin were then measured by biochemical methods in each group of the experiment. Results In the model group, the activity of GSHPX, CAT and the content of HYP of skin were all decreased significantly (P＜0. 05). And there were different degrees of improvements in those of the herb given groups. Conclusion G. Pentaphyllumhas the protective effect on the skin of the photoageing in the hairless mice. The mechanism may be that G. Pentaphyllum could inhibit the oxidative damages of ultraviolet and skin photoaging by increasing the synthesis of collagen in skin.