Protein glycosylation modification includes N-linked glycosylation, O-linked glycosylation and glycosylphosphatidylinositol anchor glycosylation. Difference from nucleic acids and proteins, the synthetic process of glycans is mainly completed by a series of glycosyltransferases which catalyze glucosidic bond, not followed the traditional central dogma of genetic information transmission. Abnormal glycosylation modification is considered to be closely related to the occurrence, development and clinical prognosis of malignant tumor. Previous studies have shown that the abnormity of glycosyltransferases expression and glycans structure affects key steps of the metastatic cascade, such as epithelial-mesenchymal-transition (E-cadherin, N-cadherin) , cell motility (integrin β1 and α5), invasion (matrix-metalloproteinases), extravasation (sLex and sLea), which by regulating the interaction between tumor cells and extracellular matrix. In this review, we mainly focus on the structures and biological functions of three glycosyltransferase families (sialyltransferases, fucosyltransferases and N-acetylglucosaminyltransferases), and their roles in tumor metastasis, hoping it can provide new ideas for the prognosis and diagnosis in tumor metastasis.