〔Abstract〕 Objective To investigate the effects of methylation expression of ADH1B gene on cell proliferation and cell apoptosis in ovarian cancer(OC) cells. Methods Bioinformatics analysis was performed to compare the relative expression of ADH1B in OC and normal tissue. Quantitative real-time PCR(qRT-PCR) was used to detect the ADH1B mRNA expression in the OC tissues or cells, ovary normal epithelium tissues or cells. Treated with different concentrations of 5-Aza-dc for 48 h, cell viability was determined by CCK-8 method. Cell apoptosis morphology was detected by Hoechst 33258 staining. The changes of promoter methylation of ADH1B, the level of ADH1B in the mRNA and protein expressions were measured by using methylation specific PCR(MSP), qRT-PCR and Western blot, respectively. Results Bioinformatics analysis and qRT-PCR showed that ADH1B expression in OC was lower than that in normal tissue. After treatment with medium and high concentration of 5-Aza-dc, the cell proliferation was inhibited in two cells(P<0.01). After treatment with high concentration of 5-Aza-dc, marked morphological changes of apoptosis was observed in two cells. ADH1B was completely methylated in two cells. ADH1B was partially reversed by high concentration of 5-Aza-dC, and ADH1B mRNA and protein expression both increased by 5-Aza-dC in two cells(P<0.01). Conclusion 5-Aza-dC can down-regulate the methylation level of tumor suppressor gene ADH1B promoter region and make it re-express in ovarian cancer cells, thus exert its function of enhancing the inhibitory effect and apoptosis of ovarian cancer cells.