Epithelial-mesenchymal transition (EMT) is a biological process whereby the epithelial cells convert into mesenchymal phenotype. Increasing studies have found and identified that EMT plays a crucial role through the multistep process of tumor metastasis from its initiation to its completion. So, it is regarded as one of the hallmarks of metastasis and is expected to be a new direction of targeted therapy. Nevertheless, there is still confusion and controversy about its nomenclature, definition, and specific value and regulatory mechanism in metastasis both at home and abroad. Therefore, a further brief review of the concept evolution of EMT and recent advances in metastasis is necessary.