Two dimensional difference in gel electrophoresis（2D DIGE） combined with high performance liquid chromatography-nano electron spray ionization tandem mass spectrometric（HPLC-nESI MS/MS） method was developed for the identification of the differentially expressed potential protein markers of human keratinocytes cell HaCaT in response to UVB irradiation,which aims to obtain the target proteins affecting the normal physiological function of skin cells induced by UVB irradiation.The results indicated that UVB irradiation could affect the integrity protein expression profile of HaCaT cell.Over 1 200 protein spots were averagely resolved on each DIGE gel by DeCyder software analysis.41 protein spots were found differentially expressed with statistical significance beyond DIGE detection limit.9 protein spots differentially expressed most significantly were successfully identified by HPLC-nESI MS/MS analysis.4 up regulated protein spots were identified as 26S proteasome subunit p405（PSMD13）,cathepsin D（CTSD）,human co chaperone P23（PTGES3） and 6 phosphogluconolactonase（PGLS）.The other 5 down regulated protein spots were identified as laminin receptor 1（RPSA）,interferon gamma inducing factor precursor（IL18）,calmodulin （CALM3）,protein similar to 60S acidic ribosomal protein P2（RPP2） and breakpoint cluster region protein 1（BANF1）.Only RPSA,CALM3 and CTSD proteins have been reported to be associated with skin burns and wound healing,proliferation and migration of keratinocytes and epidermal barrier repairing process.No study has been reported on the associations of the rest 6 proteins with damages from skin and skin cells.These 9 proteins are potential indicators for skin cells responding to UVB irradiation.The results from the current work provide valuable clues to effective protection for skin diseases at molecular level.