OBJECTIVE： To explore the effects of tamsulosin on proliferation and apoptosis in prostatic cancer PC-3 cells. METHODS： After treated with 0 （blank control group）， 12.5， 25 and 50 μmol/L tamsulosin （tamsulosin low， medium and high-concentration groups） for 48 h， the viability of PC-3 cells was detected by MTT method. Hoechst 33258 staining was used to detect cell apoptosis rate. Western blot was used to determine the expression level of Bax and Bcl-2 protein， and the phosphorylation level of protein kinase B （Akt）， mammalian target rapamycin （mTOR）， ribosomal S6 protein kinase （p70S6K） and 4E binding protein 1 （4E-BP1）. RESULTS： Compared with blank control group， PC-3 cells viability and the phosphorylation level of Akt， p70S6K and 4E-BP1 decreased in tamsulosin low， medium and high-concentration groups， while expression level of Bax protein increased （P＜0.05 or P＜0.01）； the apoptosis rate of PC-3 cells was increased in tamsulosin medium and high-concentration groups， while the expression level of Bcl-2 and phosphorylation level of mTOR were decreased （P＜0.01）， in concentration-dependent manner. CONCLUSIONS： Tamsulosin can inhibit PC-3 cells proliferation and induce cell apoptosis via blocking Akt/mTOR signal pathway.