Abstract: The aim of this study was to investigate the effect and mechanisms of miR-29a in migration and invasion of human breast cancer MCF-7 cells in vitro. MCF-7 cells were treated with miR-29a mimic or miR-29a inhibitor to up-regulate/down-regulate the expression level of miR-29a. Wound-healing assay and transwell chamber were employed to determine cell migration and invasion in vitro. The target gene of miR-29a was predicted with the Targetscan7. 1 database and verified through luciferase reporter method. The effects of miR-29a on the expression of the potential target were detected by Western blot and real-time PCR. Results showed that in vitro migration and invasion ability of MCF-7 cells was increased significantly by miR-29a, which could target HBP1 in the 3′-UTR region. The protein expression of HBP1 was decreased by miR-29a overexpression. However, the alteration of miR-29a had no significant effect on the expression of HBP1 mRNA. The results validated that miR-29a, highly expressed in breast cancer, could down-regulate HBP1, which in turn promotes migration and invasion ability of breast cancer cells, thus promoting breast cancer metastasis.