Abstract: Objective: To study the expression of Notch1 in the esophageal squamous carcinomacell line EC9706 and the effect of activated Notch1 on apoptosis of EC9706 cells. Methods: The ex-pression of Notch1 in EC9706 was detected using immunocytochemistry. RT-PCR was used to amplifythe Notch1 gene and then the eukaryotic expression vector pcDNA3.1-Notch1 was constructed and was used to transfect the EC9706 cells. Western blotting was used to detect Notch1 in the transfected cells,parental cells, and empty vector-transfected cells at 12h, 24h, 48h, and 72h. Apoptosis was also ob-served. Results: The expression of Notch1 protein was very low in the EC9706 cells. There was a sig-nificant difference in the expression level of Notch1 between EC9706 transfected with Notch1-pcD-NA3.1 and EC9706 transfected with pcDNA3.1 alone (F=80.442,P<0.05). The expression level ofNotch1 in EC9706 transfected with Notch1-pcDNA3.1 at 12h was 4.6 times higher than in EC9706 transfected with empty vector (P<0.01). However, at 48h and 72h there was no significant difference inthe expression of Notch1 between the EC9706 transfected with Notch1-pcDNA3.1 and cells transfected with empty vector (P>0.05). Inverted microscopy showed considerable apoptosis of EC9706 occurred at 48h and 72h. These results indicate that the enhancement of Notch1 expression activates Notch1 signalpathways in EC9706 and promotes apoptosis at 48h and 72h. Conclusion: The activation of Notch1 inesophageal cancer cell gives rise to a great deal of apoptosis, suggesting that the Notch1 gene could bea new target for esophageal cancer treatment.