Objective: To investigate the expression of miR-124 in colon cancer and its actions on the biological behaviors of colon cancer cells as well as the potential mechanism. Methods: The expressions of miR-124 in colon cancer tissue and cells were examined by qRT-PCR. In colon cancer cells after up-regulating miR-124 expression through lentiviral vector transfection technique, the change in apoptosis was examined by flow cytometry. Nude mice were injected with colon cancer cells of different miR-124 expression levels, and then, the pulmonary metastasis and survival time were observed. The target genes of miR-124 were predicted by bioinformatic analysis, followed by identification and verification through dual luciferase reporter assay and a series of in vitro and in vivo experiments. Results: The miR-124 expression was significantly reduced in colon cancer tissue, and its expression was significantly associated with the tumor size, tumor stage and lymph node metastasis (all P<0.05). The miR-124 expression level was decreased with the increase of the degree of malignancy of the colon cancer cells. After up-regulation of miR-124 expression, the apoptosis of colon cancer cells was significantly increased, pulmonary metastasis was inhibited and survival time was prolonged in the nude mice (all P<0.05). ITGB1 was suggested as the potential target gene for miR-124. In colon cancer cells, down-regulating ITGB1 expression showed the similar effects as those exerted by up-regulating miR-124 expression. There was a negative correlation between miR-124 and ITGB1 expressions in colon cancer tissue (r=–0.4936, P=0.002). Conclusion: The miR-124 expression is down-regulated in colon cancer, with accordingly increased expression of its target gene ITGB1, which promotes the growth as well as the invasion and metastasis of the colon cancer cells.