Abstract：Objective：To study the ability of bufalin to induce apoptosis and cycle arrest of human colon cancer HT- 29 cell， and to explore its molecular mechanism. Methods： Human colon cancer HT- 29 cells was divided into control group (wild- type cells) and bufalin treatment group(0.25， 0.5， 1 μmol/L) and cisplatin(DDP) group(1 μg/mL). The apoptosis and cycle arrest of human colon cancer HT- 29 cell induced by bufalin were detected by flow cytometry(FCM). Western blotting was used to detect the changes of protein expression of phosphatidylinositol- 3 kinase(PI3K)， phosphorylated phosphatidylinositol- 3 kinase(p- PI3K)， protein kinase B(Akt) and phosphorylated protein kinase B(p- Akt) in HT- 29 cells treated with bufalin for 24 hours. The effect of bufalin on the mRNA expression of PI3K and Akt in HT-29 cells was detected by real-time fluorescence quantitative PCR(RT-qPCR). Results：The results of FCM showed that compared with the control group，bufalin(0.25，0.5，1 μmol/L) group could induce apoptosis of colon cancer HT-29 cell in a dose-dependent manner (P＜0.05). Compared with the control group，bufalin(0.25，0.5，1 μmol/L) group could induce the cycle arrest of colon cancer cell line HT-29 in G2/M phase，and the greater the concentration of bufalin，the more significant the cycle arrest effect(P＜ 0.05). Western blot results showed that compared with the control group，bufalin could down regulate the expression levels of PI3K，p-PI3K，Akt and p-Akt in a dose-dependent manner(P＜0.05). RT-qPCR results showed that compared with the control group， bufalin could significantly down regulate the expression of PI3K and Akt mRNA. Conclusion： Bufalin can induce apoptosis and cycle arrest of colon cancer HT-29 cell，and its mechanism may be related to the inhibition of PI3K/Akt signal pathway.