Abstract: Objective: To investigate the in vitro effect of Trichostatin A (TSA) on Hela human cervical cancer cells in order to reveal its probable mechanism and to elucidate the relationship between apoptosis and the expression of human telomerase reverse transcriptase (hTERT). Methods: Inverted phase contrast microscopy (IPCM) was used to observe morphologic changes in the cells. Sulforhodamine B was employed to determine the pharmacokinetic characteristics. Flow cytometry(FCM)was conducted to measure apoptosis before and after drug treatment. The expression levels of hTERT and p21/Waf1 mRNA, before and after Trichostatin A treatment, were detected using semi- quantitative reverse transcription polymerase chain reaction (RT- PCR). The hTERT protein expression level before and after TSA treatment was detected by fluorescence microscopy. Results: After being treated with 0.1μM, 0.5μM, 1.0μM, and 2.0μM Trichostatin A, the proliferation of Hela cells was significantly inhibited. IPCM showed that there were obvious morphologic changes after TSA treatment. Changes in the cell cycle occurred 48 h after treatment, and with a dose of 2.0μmol/L TSA apoptosis was apparent.hTERT expression was down- regulated after treatment with 1.0μmol/L TSA, in a time- dependent manner. Immunofluorescence detection showed that there was decreased expression of the hTERT protein after the 1μmol/L TSA treatment. Conclusion: Trichostatin A significantly inhibited growth of Hela cells by inducing apoptosis and the mechanism may be related to a down- regulation in hTERT expression.