Abstract: Objective:To determine the expression of BMP4 in hepatocellular carcinoma (HCC) and to study the role of BMP 4 in inducing epithelial-mesenchymal transition (EMT) to analyze the effect of BMP 4 on the migration and invasion of HCC cells. Methods:The expression of BMP 4 in HCC specimens was examined by immunohistochemistry staining, and the correlations were analyzed between the expression of BMP4 and clinicopathological data. The BMP4 expression plasmid was transfected into HepG2 cells to induce exogenous overexpression of BMP4 protein. The changes of HepG 2 cell morphology were detected after BMP 4 transfection by using a microscope; the changes of the expression of BMP4, EMT-related protein (E-cadherin, Vimentin) in HepG 2 cells were detected by Western blot after transfection of BMP 4; the wound healing assay in vitro was used to detect the effects of BMP4 gene transfection on the ability of migration of HepG 2 cells; the invasion assay was used to determine the role of transfection of BMP 4 on the invasive potential of HepG 2 cells. Results: Immunohistochemistry staining method displayed that BMP4 expression was positively associated with age, histological differentiation, stage, and poor prognosis. After BMP 4 overexpression, the morphology of HepG2 cells showed significant changes from a paving stone structure with cell-cell adhesion to a fibroblastic shape, which showed typical EMT change; Western blot exhibited that the expression of E-cadherin was downregulated and the Vimentin expression was upregulated in HepG 2 cells; the wound healing and invasion assay showed that the migration and invasion potentials of HepG 2 cells were significantly enhanced. Conclusion:BMP4, which displayed a high expression in HCC specimens, was closely associated with clinicopathologic data, and BMP4 may promote migration and invasion of HCC cells by inducing epithelial-mesenchymal transition.