To achieve the synthesis of glycoproteins with homogeneous N-glycans, advanced chemical synthetic methods have been developed. Solid-phase peptide synthesis (SPPS) was optimized specifically for the production of acid-labile glycopeptides. A semisynthetic method for obtaining homogeneous N-glycans has also been developed, involving their isolation from egg yolk. The resulting glycopeptides, along with other peptides, can be coupled in aqueous solution through native chemical ligation (NCL). Furthermore, the final folding of glycoproteins was studied to produce homogeneous glycoproteins. Using these homogeneous glycoproteins, the functions of N-glycans have been evaluated. This review highlights the development of the synthesis of homogeneous glycoproteins and their applications.