Abstract: OBJECTIVE To investigate the proliferation and possible mechanism of rat's cerebral microvascular endothelial cells induced by low dose FasL.METHODS 9 FasL of different concentration gradients was diluted 500~0.015 6 ng/mL 1/2 multiple proportion and the cell culture of bEnd.3 was interfered by 48 h. The cell proliferation ability of bEnd.3 was tested by CCK-8. The VEGF cell secreted expression ability of bEnd.3 was tested by ELISA. Fas Expression was inhibited by RNAi. The protein express levels of FADD， FLIP and TRAF were tested by Westernblot， and the protein express level of NF-κB was tested by EMSA.RESULTS bEnd.3 cell interfered by 0.156 ng/mLFasL could obviously induce the cell proliferation to increase(P<0.05). VEGF cell secreted expression ability of bEnd.3 was markedly increased(P<0.05). The protein express levels of FADD，FLIP，TRAF and NF-κB increased significantly(P<0.05); The cell proliferation and protein express levels of NF-κB did not change significantly although Fas gene was inhibited by RNAi(P>0.05). The protein express levels of FADD， FLIP， TRAF decreased obviously when Fas gene was inhibited by RNAi(P<0.05). CONCLUSION Low dose FasL can induce the cell proliferation of bEnd.3， and FADD-FLIP-TRAF-NF-κB signal transduction pathway is one of its mechanisms.