Objective To investigate the expression of markers for epithelial-mesenchymal transition (EMT) during the development of ductal plate in human liver, so as to discuss the role of EMT during ductal plate development in the liver. Methods Immunohistochemical method was used to examine the expression of EMT markers (CK19, vimentin, and α-SMA) in the liver tissues of 31 fetuses of 8-40 weeks old. Results From the 8^th gestation week onwards (ductal plate phase, remodeling phase of ductal plate, and formation phase of bile ducts), the CK19-positive cells in the portal tract were gradually increased, vimentin/α-SMA-positive portal mesenchymal cells were gradually decreased, and CK19-positive cells were negatively correlated with vimentin/α-SMA expression ones (vimentin: r=-0.820, P<0.001; α-SMA: r=-0.797, P<0.001). The ductal plate cells began to express vimentin at the 9^th week of gestation, the expression peaked in the fetal liver during 13-19 weeks of gestation, and then it was gradually declined and became undetectable at the 28^th week. Some immature bile duct epithelial cells showed cytoplasmic immunostaining of vimentin from 14 to 32 weeks of gestation. Furthermore, integration and transition were observed between vimentin-positive portal myofibroblasts (pMFs) and ductal plate cells or bile ducts. In serial section of the developing human liver (9-32 weeks), we observed that ductal plate or bile ducts cells co-expressed vimentin and CK19. Conclusion Our findings show the presence of mesenchymal-epithelial transition during the development of ductal plate in human liver, which is associated with the formation of bile ducts.