Abstract: Objective To investigate the change of apoptosis in paclitaxel resistant cell line of human esophageal carcinoma Ec9706/P-1. Methods The expression levels of Bcl-2,caspase-3 and NF-κB were detected by semi-quantitive reverse transcription-polymerase chain reaction(RT-PCR) assay.The expressions of Bcl-2 protein,Caspase-3 protein and NF-κB protein were determined by immunohistochemistry.DNA fragments were resolved by agarose gel electrophoresis to detect cell apoptosis.Apoptosis rates and morphology were detected by acridine orange(AO) fluorescent staining. Results The expression levels of bcl-2 and NF-κB in Ec9706/P-1 cells were significantly higher than those in Ec9706 cells (P<0.05).The expression level of caspase-3 in Ec9706/P-1 cells was decreased significantly (P<0.05),compared with Ec9706 cells.Immunohistochemistry assay showed that positie expression rates of Bcl-2 and NF-κB in Ec9706/P-1 cells were higher than those in Ec9706 cells statistically (P<0.05).The positive expression rate of Caspase-3 protein in Ec9706/P-1 cells was significantly lower than that in Ec9706 cells (P<0.05). Conclusion The possible mechanisms of acquired resistance of Paclitaxel-resistant human esophageal carcinoma cell line Ec9706/P-1 may be caused by overexpression of Bcl-2 and NF-κB,down-regulation of Caspase-3.Ec9706/P-1 cells escaping from apoptosis may be one of resistant mechanisms.