Abstract: Ginseng pectin is a mixture of heteroglycans, By isolation ands purification the homogeneous S_A-1 was obtained which contains galactose, galacturonic acid, arabinose and rhamnose residues in the molar ratio of 3.7:1.7:1.8:1.Structural studies of S_A-1 were performed by periodate oxidation, Smith degradation and methylation etc. The carboxyl groups in the S_A-1 were reduced by Taylor. and Conrad methods: The alditol acetates obtained from methylatioh of S_A-1 and acetylation of its hydrolysate were identified by GC and GC-MS.The results of these studies indicate that S_A-1 is a highly branched molecule with β (1-3)D-galactan as its backbone. There are side chains on some of the galactose residues at C₆′ position. The galacturonic acid residues (1-4), Rhamnose residues (1-3 or 1-2,4), arabinose (1-5 or 1-3,5) are found in the side chains. Besides, the (1-6) linkage of galactose residues is also present.