Objective　To　perform　structural　analysis　on　the　homogeneous　polysaccharide　SP800301　isolated　from　Saposhnikoviae　Radix　to　determine　its　chemical　structure.　Methods　Polysaccharides　were　separated　and　purified　from　Saposhnikoviae　Radix　using　column　chromatography,　such　as　DEAE-cellulose　and　Sephadex　G　-　75.　The　molecular　weight　distribution,　monosaccharide　composition,　oligosaccharide　fragments,　sugar　residue　types,　and　glycosidic　bond　connection　of　the　isolated　homogeneous　polysaccharide　SP800301　from　Saposhnikoviae　Radix　were　analyzed　using　electrospray　ionization　multistage　mass　spectrometry,　gas　chromatography-mass　spectrometry,　and　nuclear　magnetic　resonance　to　determine　its　structure.　The　appearance　characteristics　of　the　Saposhnikoviae　Radix　polysaccharide　were　characterized　using　electron　and　atomic　force　microscopy.　Results　Polysaccharide　SP800301　extracted　from　Saposhnikoviae　Radix　had　good　homogeneity　with　a　molecular　weight　of　9.　1　×　104　g　/　mol.　The　uronic　acid　content　was　52.　72%.　The　monosaccharide　group　comprised　rhamnose,　galacturonic　acid,　glucose,　galactose,　and　arabinose,　with　a　molar　ratio　of　4.　3:58.　1:25.　4:5.　0:7.　3.　The　polysaccharide　was　mainly　composed　of　polygalacturonic　acid　as　the　primary　chain.　The　branched　chain　was　comprised　of　rhamnose,　galacturonic　acid,　galactose,　glucose,　and　arabinose,　with　arabinose　at　the　end　of　the　branched　chain　and　part　of　the　galacturonic　acid　in　the　sugar　chain　forming　a　methyl　ester.　Conclusion　This　study　clarified　the　chemical　structure　of　the　homogeneous　polysaccharide　SP800301　from　Saposhnikoviae　Radix,　enriched　the　chemical　composition　of　Saposhnikoviae　Radix　polysaccharides,　laid　the　foundation　for　further　research　on　the　immune　regulatory　mechanism　of　Saposhnikoviae　Radix　polysaccharides,　and　provided　a　scientific　basis　for　clinically　using　Saposhnikoviae　Radix.　©　2024　Editorial　Department　of　Journal　of　Beijing　University　of　Traditional　Chinese　Medicine.　All　rights　reserved.