[Objective]To explore the radiosensitization and radiation protection effects of aged black garlic extract on colon cancer Ht-29 in mice induced by60Co γ ray and to primarily discuss its molecular mechanism. [Methods] Transplant subcutaneous sarcoma model of colon cancer Ht-29 in mice was constructed. 40 tumor-bearing mice were divided into 4 groups: blank control group,γ ray group,black garlic group and black garlic combined with γ ray group. Mice in these groups were treated with NS,γ ray,black garlic extract and black garlic extract combined with γ ray. The growth rate of transplantation tumor in various groups were observed and also the tumor growth delay of transplantation tumor in treatment groups. Eyeballs were removed to achieve blood and then mice were put to death by break necks. Tumors were obtained and weighed. The growth inhibition ratio of tumor was calculated. The expression of Bcl-2,Bax and Caspase-9 was determined by Real-time-PCR. The validity of SOD and CAT was measured by white blood count and UV spectrophotometry. [Results]Black garlic extract combined with γ ray had growth inhibition effect on transplantation tumor in colon cancer Ht-29 mice. It could prolong the time of tumor growth and increase the radiosensitivity. It could also down-regulate the expression of Bcl-2 in transplantation tumor tissue and up-regulate the expression of Bax. As a result,it could enhance the expression of Caspase-9 protein( P < 0. 05). Black garlic extract could increase the number of peripheral white blood cells and enhance the validity of SOD and CAT. [Conclusions]Black garlic extract could increase the radiosensitivity of γ ray on colon cancer Ht-29 transplanted tumor in mice by down-regulation of Bcl-2,up-regulation of Bax and activating the expression of Caspase-9 protein.It could also enhance radiation protection by increasing the number of peripheral white blood cells and the antioxidant ability. [Objective] To explore the radiosensitization and radiation protection effects of aged black garlic extract on colon cancer Ht-29 in mice induced by 60Co gamma ray and to be consulted on its molecular mechanism. [Methods] Transplant subcutaneous sarcoma model of colon cancer Ht-29 in mice were constructed. 40 tumor-bearing mice were divided into 4 groups: blank control group, γ ray group, black garlic group and black garlic combined with γ ray group. Mice in these groups were treated with NS, γ ray, black garlic extract The growth rate of transplantation tumor in various groups were observed and also the tumor growth delay of transplantation tumor in treatment groups. Eyeballs were removed to achieve blood and then mice were put to death by break necks. The expression inhibition of Bcl-2, Bax and Caspase-9 was determined by Real-time-PCR. The validity of SOD and CAT was measured by white blood count and UV spectrophotometry. [Results] Black garlic extract combined with γ ray had growth inhibition effect on transplantation tumor in colon cancer Ht-29 mice. It could prolong the time of tumor growth and increase the radiosensitivity. It could also also down-regulate the expression of Bcl-2 in transplantation tumor tissue and up-regulate the expression of Bax. As a result, it could enhance the expression of Caspase-9 protein (P <0.05) number of peripheral white blood cells and enhance the validity of SOD and CAT. [Conclusions] Black garlic extract could increase the radiosensitivity of γ ray on colon cancer Ht-29 transplanted tumor in mice by down-regulation of Bcl-2, up-regulation of Bax and activating the expression of Caspase-9 protein. It could also enhance radiation protection by increasing the number of peripheral white blood cells and the antioxidant ability.