The authors chose specimens from nine normal prostate tissues(NP group),15 benign prostate hyperplasia(BPH) prostates(BPH group),and 35 BPH prostates that had been treated with 90Sr/90Y Prostatic Hyperplasia Applicator(exposure group),The expressions of bcl-2 and bax in stroma and epithelia of prostate tissues were demonstrated by means of immunohistochemical staining,and the staining positive rate was semiquantatively determined,so as to observe the expression of bcl-2 and bax genes in the prostate tissues of normal individuals and BPH patients,before and after β radiation,and to evaluate the influence of β radiation on bcl-2 and bax expressions,The expressions of gene bcl-2 in the prostate epithelia of NP and BPH are significantly higher than those in the prostate stroma(P＜0.01),However,the expressions of bcl-2 in the prostate epithelia and stroma of the BPH group are obviously higher than those in the NP group(P＜0.01),The expression of gene bax in the prostate epithelia of the NP group is higher than that in the BPH group(P＜0.05),However,bcl-2 expressions in the prostate epithelia and stroma of the BPH group are significantly higher than the bax expressions(P＜0.01),Compared with those of the NP group,the expressions of bcl-2 in the prostate epithelia and stroma of the exposure group decrease remarkably,even as the expressions of the bax notably increase(P＜0.01),Thus,the administration of β radiation can remarkably affect bcl-2 and bax gene expressions,to regulate cell apoptosis,in the prostate tissues of BPH.