Objective To detect the expression of miR-346 in colon cancer cells and the relationship with invasion and metastasis, so as to provide experimental basis for predicting and treating targets of colon cancer. Methods Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of microRNA-346 in colon cancer cell lines ( HCT116, COLO205, SW620) and normal colon epithelial cells ( NCM460 ) . The expression of microRNA-346 was up-regulated or down-regulated by mimic or inhibitor and transfected into HCT116 cells. The transfection efficiency was detected by qRT-PCR. The metastasis and infiltration behavior of HCT116 cells were observed by Transwell. Results The relative expression of microRNA-346 in colon cancer cell lines HCT116, COLO205 and SW620 were (0. 372±0. 068),(1. 284±0. 253),(1. 105±0. 203),respectively. The relative expression of COLO-205 and SW620 in normal colon epithelial cells (NCM460) was (0. 126±0. 004). Compared with NCM460 group, COLO-205 group and SW620 group had significant difference (t＝9. 652,P＜0. 01; t＝7. 753,P＜0. 01). The invasion and metastasis ability of HCT116 cells increased after the up-regulation of the expression of microRNA-346 (t＝2. 458,P＜0. 05; t＝2. 194,P＜0. 05),and decreased after the down-regulation of the expression of microRNA-346 (t＝2. 247,P＜0. 05; t＝2. 065,P＜0. 05) . Conclusion Mir-346 is highly expressed in colon cancer cells and regulates invasion and metastasis of colon cancer cells.