Abstract: Objective : To investigate the effect of TNF-α on the expression of Notch1 for better understanding a novel mechanism for the neogenic capacity of Notch1 in Raji cell lines and elucidation of the effect of activated Notch1 signaling in Raji cell lines. Methods : The effects of triptolide on the proliferation of Raji cells were tested using MTT; the mRNA level of Notch1 in Raji cell line treated by TNF-α and triptolide was measured by RT-PCR. The change of expressions of Notch1 protein was tested by flow cytometry. Results : a) Triptolide inhibited the proliferation of Raji cells in a dose- and time-dependent manner. b) Triptolide reduced the Notch1 mRNA level in a dose-dependent manner compared with the controls in Raji cells. The Notch1 mRNA level increased after treated by TNF-α (P0.01). c) Flow cytometry also showed increased level of Notch1 protein induced by TNF-α, and TRL inhibited the expression of Notch1 protein in Raji cells. Conclusion : Notch1 protein is expressed in Raji cells. TNF-α and triptolide can play a role through affecting Notch1 signaling and that it might be a potential new target for treatment.