Objective: The purpose of this study is to clarify the roles of tocopherol submicron emulsion (VitE SME) in UVB-induced damage to HaCaT keratinocytes. Methods: VitE SME was prepared by high pressure homogenization and microemulsion technique. HaCaT keratinocytes were incubated in the culture medium supplemented with 1/200 and 1/400 of VitE SME before different dosages of UVB irradiation. The VitE level in the culture medium was measured by HPLC. Cell growth and cellular activity were detected by MTT assay. Results: The VitE level in the culture medium significantly decreased during the first 8 h, and less than 10% can be detected by 24 h. In contrast to control group, the cellular activity of VitE SME treated group increased 44.22% by 24 h. Compared with irradiated groups without VitE SME, irradiated groups with VitE SME the cell proliferation decreased by 17.77% and 40.42% when irradiated with 30 mJ/cm2 and 90 mJ/cm2, respectively. Conclusions: VitE SME has no toxicity to cell culture system and has good releasing and penetrating ability. The photoprotective efficiency of VitE SME to UVB also shows time-dependent increase. Pre-incubation with VitE SME can partly reduce UV-induced cell damage.