Abstract: Objective To investigate the effect of miR-101 on biological behaviors of colorectal cancer cell line SW620. Methods CCK-8 method, colony formation assay, cell cycle analysis and apoptosis analysis were applied to assess the effects of miR-101 on cell proliferation, invasion and apoptosis of SW620 cells. Results Over-expression of miR-101 in SW620 cells significantly suppressed the cell proliferation and attenuated the colony-forming ability of the cells. Flow cytometry showed that over-expression of miR-101 in SW620 cells caused obvious cell cycle arrest in G2/M and G1 phases, and significantly increased the cell apoptosis rate. Conclusion Over-expression of miR-101 can inhibit the proliferation, cause cell cycle arrest and promote apoptosis of colorectal cancer SW620 cells.