The aim of the study was to investigate the inhibitory effects of RNA interference on XIAP gene expression of human endometrial carcinoma RL95-2 cell and the cell apoptosis. Specific small interference RNA (siRNA) of XIAP was designed and composed. Transfection of siRNA was conducted in endometrial carcinoma cell line RL95-2. The XIAP gene mRNA was assessed by real-time PCR and the change of XIAP protein was assessed with Western Blotting. The cell proliferation and apoptosis was assessed by MTT and flow cytometry methods. After transfection of siRNA specifically targeting XIAP, the relative fold of mRNA transfection in the specific transfection group was (0.04 ± 0.06) and the relative protein expression was (0.590 ± 0.178), which was significantly decreased when compared with the control group (P < 0.05); the cell growth inhibition rate in the transfection group was (47.86 ± 4.46)%, which was significantly increased when compared to the control group (P < 0.05). In vitro experiment showed that synthetic siRNA could effectively inhibit the transfection and expression of XIAP gene of human endometrial carcinoma RL95-2 cell at the mRNA level and protein level, thus significantly promote the apoptosis of endometrial carcinoma cell. The mechanisms involved in the apoptosis still require further investigation.