The biological function of complex carbohydrates represented by polysaccharide is fundamentally determined by their structural composition. However， the complexity inherent in polysaccharides structure and the lack of adequate theoretical guidance for their characterization has impeded progress in this field. To address these issues， this review aimed to comprehensively introduce key methods for polysaccharide extraction， isolation， purification， and structural analysis， with a particular focus on the essential components required for constructing analytical methods and theoretical system for polysaccharide structure characterization. Firstly， polysaccharides generally exhibit the structural characteristic of 'relative ordered structure'. Subsequently， effective separation and purification of polysaccharides can be achieved through the implementation of 'three consecutive and progressive stages' purification strategy， which involves a universal evaluation of the homogeneous components obtained from purification using a multidimensional approach. Additionally， to ensure scientific precision and repeatability in polysaccharide structural characterization， the core technology of 'partial degradation-methylation-NMR' is employed. An assessment was also conducted to determine adherence to the theory of 'relative ordered structure' to obtain replicable outcomes. Finally， a comprehensive overview of the future research directions in polysaccharide structure analysis was summarized.