Objective：To investigate the effects of 5-aza-2’-deoxycytidine（5-Aza-CdR） on the proliferation and apoptosis in human endometrial cancer（HEC）HEC-1-B cells and the possible mechanism. Methods：HEC-1-B cells were treated with different concentrations of DNA methytransferase inhibitor 5-Aza-CdR. Methylation-specific polymerase chain reaction（MSP） was used to detect pro－moter methylation status of RAS association domain family 1A（RASSF1A） gene and RT-PCR was used to detect re-expression of mRNA. Furthermore，cell growth was estimated by MTT assay and cell apoptosis rate was estimated by flow cytometry. Results：Promoter hypermethylation of the RASSF1A gene was detected in HEC-1-B cells. After treatment with 5-Aza-CdR，the promoter region of the RASSF1A gene exhibited a demethylation status，and RASSF1A gene was re-expressed. Meanwhile，the cellular growth activity decreased and cell apoptosis increased. Conclusions：The 5-Aza-CdR could reverse methylation of RASSF1A gene to regulate the expression of RASSF1A gene，and could effectively inhibit the cellular proliferation and induce apoptosis of endometrial carcinoma cells.