Abstract: Objective: Anti-growth effects of fat-soluble alkaloids extracted from Dendrobium Nobile Lindl on human colorectal cancer HT-29 cells and its possible apoptotic mechanism were studied.Methods: The MTT assay was used to assess the effect of fat-soluble alkaloids extracted from Dendrobium Nobile Lindl on survival rate of HT-29 cells; the morphological changes of HT-29 cells were observed with Hoechst 33342 staining; the levels of intracellular reactive oxygen species( ROS),mitochondrial membrane potential( ΔΨm),cell cycle distribution and apoptosis rate were studied using flow cytometry; western blotting analysis was used to detect the expressions of Caspase-9,3,and intracellular cytochrome C. Results: Fat-soluble alkaloids extracted from Dendrobium Nobile Lindl decreased survival rate of human colorectal cancer HT-29 cells in a doseand time-dependent manner; IC_50 value for 48 h was 0.72 mg / mL. Fat-soluble alkaloids extracted from Dendrobium Nobile Lindl induced cell apoptosis and cell cycle was arrested in G2 phase; it caused decline of ΔΨm and induced ROS accumulation with increased expression levels of apoptotic proteins such as activated Caspase-9,activated Caspase-3,and level of intracellular cytochrome C.Conclusion: Fat-soluble alkaloids extracted from Dendrobium Nobile Lindl can inhibit the growth of HT-29 cells and induce cell apoptosis,which may be associated with the involvement of the mitochondria-mediated apoptotic pathway.