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Background miR-222 has been reported to be overexpressed in colorectal cancer and it influences cancer cell proliferation, drug resistance and metastasis. However, the underlying molecular mechanism of miR-222 in colorectal cancer cell invasion and migration has not been thoroughly elucidated to date. Methods The cell cycle distribution and apoptosis were assessed by flow cytometry. Cell migration and invasion were analyzed by Transwell assays. The possible target gene of miR-222 was searched and identified by bioinformatics, dual luciferase reporter assay and western blot analysis. The siRNA method was used to confirm the function of the target gene. Results Overexpression of miR-222 effectively promotes migration and invasion of colorectal cancer (CRC) cells in vitro. Bioinformatics and the dual luciferase reporter assay revealed that miR-222 specifically targeted the 3′-UTR of melanoma inhibitory activity member 3 (MIA3), down-regulating its expression at the protein level. Inhibition of MIA3 by siRNA enhanced the migration and invasion of CRC cell lines. Conclusions Our study showed that miR-222 enhances the migration and invasion in CRC cells, primarily by down-regulation of MIA3. Electronic supplementary material The online version of this article (doi:10.1186/s12935-017-0447-1) contains supplementary material, which is available to authorized users.