The structure of polysaccharides from Ganoderma (PSG) are complicated and diversified. However, due to the excellent bioactivities, PSG have attracted extensive attention. Structure is the fundamental for the bioactivity of PSG. In recent years, lots of research work were devoted to the structural characterization in order to establish the structure-bioactivity relationship of PSG. This paper provided a comprehensive overview of research on the structure of PSG. The chemical composition, primary structure and solution conformation were highlighted. Based on the modern instrumental analysis, the methodology for the structural characterization of PSG have also been reviewed, which were expected to provide references for the deeply study on the primary and advanced structure of PSG.