Glycomics represents a novel omics technology developed after the genomics and proteomics, which focus on the glycan structure and function．As a group of biomolecule, glycans provide and store energy within the cell, and play many significant roles in physiological and pathological processes, such as cell-cell recognition and inflammatory and autoimmune diseases．Structural analysis of glycan is the bottleneck of glycomics research, due to their macro-heterogeneity (site occupancy) and micro-heterogeneity (different glycoforms attached to one glycosylation site). Comparing with traditional analysis approaches, mass spectrometry has become the method of choice for structural analysis methods in glycan, thanks to its ability to require minute amounts of sample, gain more different information and to be used in combination with high-throughput analysis methods. This paper summarizes the advance in our understanding of glycan structures using mass spectrometry (MS), including multistage mass spectrometry (MSⁿ), LC-MS and CE-MS.