Objective To explore the protective effect of schisandrin B (SchB) on the permanent damage of human keratinocytes (HaCat) induced by long wave ultraviolet (UVA),and its possible mechanism thereof. Methods After HaCat was treated by 5 J/cm2 UVA, different concentrations of SchB (0.1, 0.01, 0.001 and 0.000 1μmol/L) were used to treat HaCat cells. The levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activity, lactate dehydrogenase (LDH) and NO content were detected. Results The levels of SOD and GSH-Px activity were decreased, and he levels of LDH and NO content were increased in HaCat cells after being treated by UVA. The different concentrations of SchB showed significant ef-fects on the increased levels of SOD, GSH-Px activity and decreased levels of LDH and NO, and improved the survival rate of HaCat cells. The 0.001 μmol/L SchB showed the strongest protective effect. Conclusion The 0.001 μmol/L SchB showed the best effect on the damage of HaCat cells induce the UVA.