Glycosylation has significant impacts on the efficacy, stability, and immunogenicity of biopharmaceuticals. Among these, the oligosaccharide spectrum and glycan structure are important indicators for assessing the characteristics of biopharmaceuticals. Oligosaccharides, as important carbohydrates, participate in various cellular life processes, such as protein folding and signal transduction. In addition, oligosaccharides often bind with proteins to form glycoproteins.