To study the effect of chenodeoxycholic acid(CDCA) on HCT-116 in colon cancer cells and to explore its mechanism. Methods: In vitro cell culture, MTT method, hematoxylin-eosin staining, Giemsa staining, acridine orange /ethidium bromide staining (AO /EB Staining) and flow cytometry were used to detect the effect of CDCA on the survival rate, morphological changes, cell cycle, mitochondrial membrane potential and apoptosis rate of colon cancer HCT-116 cells. Results: The results showed that the inhibitory rate of CDCA on the colon cancer cell HCT-116 cell line was 48.4 h after 48 h of 0.304 mmol /L, 0.800 mmol /L for 58 h, and the cell volume Shrinkage, nuclear condensation and chromatin condensation and other apoptotic morphological changes. The results of flow cytometry showed that the cell cycle was blocked in G2 / M phase and decreased by mitochondrial membrane potential after transfection with chenodeoxycholic acid(CDCA). The apoptotic rate of HCT-116 cells was 54.5 h after treatment with 0.400 mmol /L CDCA for 48 h %. Conclusion: The inhibitory effect of CDCA on human colon cancer cell line HCT116 is dependent on its dose and may induce apoptosis of human colon cancer cell line HCT-116 through mitochondrial pathway.