Phytoestrogens are some plant compounds exhibiting estrogen-like activities. However, some studies have shown that they also affect the growth of some nonhormone-dependent diseases. In this study, daidzein – one of the most common phytoestrogens – was used to investigate its effects on human cervical cancer cells HeLa in vitro. First, the cell growth was measured by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Then, the distributions of cell cycle and apoptosis were analyzed with the help of flow cytometry. Finally, the telomerase activity was detected by using real-time quantitative reverse transcription-polymerase chain reaction. The results showed that at the concentrations from 6.25 to 100 µmol/l, daidzein inhibited the growth of HeLa cells. Flow cytometric analysis showed that cancer cells were arrested at G0 / G1 or G2 / M phase with daidzein. The inductive effects of apoptosis were more obviously observed in low-concentration groups. After HeLa cells were treated with daidzein, the expression of human telomerase catalytic subunit mRNA decreased. These meant that daidzein affected human nonhormone-dependent cervical cancer cells in several ways, including cell growth, cell cycle, and telomerase activity in vitro.