Objective：The aim of our research is to investigate the role of oxidative stress in cellular aging of human epidermal melanocytes. Methods：Cultured human melanocytes were subjected to different doses of H2O2（0、200、400、600、800、1 000 μmol/L）for 5 d，after which cell viability and apoptosis were assessed.Next we investigated whether exposure to low levels of H2O2（0~400 μmol/L）induces premature senescence via evaluating senescence-associated β-galactosidase staining，cell proliferation assay，cell cycle analysis，E-cadherin and senescent gene expression，etc. Results：Cell viability and apoptosis in melanocytes cultured with H2O2 at 200~400 μmol/L showed no significant difference as compared with cells cultured without H2O2 and apoptosis of melanocytes progressively increased at high concentrations of H2O2 （600~1 000 μmol/L）. Treatment with 400 uM H2O2 tended to exhibit dendrite retraction，increased SA-beta-gal activity，declined rate of proliferation，G2 cell cycle arrest，and changes in the expression levels of p53 and p21.We further show that pre-senescent melanocytes express markedly reduced levels of E-cadherin. Conclusion：Melanocytes undergo premature senescence under the stimulation of 400 μmol/L concentration of H2O2 .