Objective To explore the effects of platelet-rich plasma(PRP) on collagen and hyaluronic acid(HA) expression of light aging human skin fibroblasts(HSFs) in vitro.Methods Cultured human skin fibroblasts were radiated with ultraviolet ray and the proliferation and doubling time of cell were estimated.Different concentrations(10%,30% and 50%) of PRP were added into cultured light aging human skin fibroblasts,and HSFs radiated with ultraviolet ray were taken as negative control and HSFs were taken as positive control.ELISA was used to measure collagen expression and hyaluronic acid expression.Results The cell proliferation was prohibited after ultraviolet irradiation and cell doubling time was shortened with the increasing of PRP concentration after PRP added.ELISA assay showed that the collagen type 1(COL1),type 3(COL3) and HA expression were decreased after ultraviolet irradiation and promoted after PRP added,significant difference was shown between expermental groups and negative control group(P<0.01).Conclusion PRP can promote the synthesis of collagen type 1(COL1),type 3(COL3) and HA,and may be used as an effective factor against skin photoaging.