Objective:To explore the influence of silencing Bcl-2 expression by small interfering RNA(siRNA) on Bcl-2 protein expression,cell apoptosis rale and radiosensilivity of gastric cancer BCC823 cells.Methods:siRNA segment for Bcl-2 gene was designed and synthesized,then was induced into gastric cancer BGC 823 cells by liposome transfection.Bcl-2 protein expression was detected by Western Blotting.After X radiation,flow cytometry and clone forming assay were used to determine the effects of RNA interference on BGC823 cell apoptosis rate and radiosensitivity. Result:After the transfection of Bcl-2 siRNA,the positive expression rate of Bcl-2 protein in BGC823 cells was(35.45±2.35)%.Compared with the control group and negative siRNA transfection group,the rate was significantly decreased(P<0.01).The apoptosis rate of BGC823-RNAi cell was(10.81±0.91)%,which was significantly higher than the control group and negative siRNA transfection group(P<0.01).After 48h X radiation,the apoptosis rate of BGC823-RNAi was(28.91±1.40)%,which was significantly higher than the control group and the group without radiation (P<0.01).During clone forming assay D_0,D_4 and SF_2 values in Bcl-2 siRNA1 transfection group were all lower than those in the control group.The radiosensitivity ratio was 1.28(the ratio of D_0) and 1.60(the ratio of D_4).Conclusions:Specific siRNA of Bcl-2 gene can effectively inhibit the expression of Bcl-2 gene,enhance the radiosensitivity and apoptosis of gastric cancer BGC823 cells,having good clinical application perspective. Objective: To explore the influence of silencing Bcl-2 expression by small interfering RNA (siRNA) on Bcl-2 protein expression, cell apoptosis rale and radiosensilivity of gastric cancer BCC823 cells. Methods: siRNA segment for Bcl-2 gene was designed and synthesized , then was induced into gastric cancer BGC 823 cells by liposome transfection. Bcl-2 protein expression was detected by Western Blotting. After X radiation, flow cytometry and clone forming assay were used to determine the effects of RNA interference on BGC823 cell apoptosis rate and The positive expression rate of Bcl-2 protein in BGC823 cells was (35.45 ± 2.35)%. Compared with the control group and negative siRNA transfection group, the rate was significantly decreased ( P <0.01). The apoptosis rate of BGC823-RNAi cell was (10.81 ± 0.91)%, which was significantly higher than that of the control group and negative siRNA transfection group fCBC823-RNAi was (28.91 ± 1.40)%, which was significantly higher than the control group and the group without radiation (P <0.01). lower than those in the control group. The radiosensitivity ratio was 1.28 (the ratio of D_0) and 1.60 (the ratio of D_4) .Conclusions: Specific siRNA of Bcl-2 gene can effectively inhibit the expression of Bcl-2 gene, enhance the radiosensitivity and apoptosis of gastric cancer BGC823 cells, having good clinical application perspective.