In this study, a novel neutral non-starch polysaccharide (GP1A) was extracted using hot water from ginseng roots. Chemical characteristics, monosaccharide compositions and structure of GP1A were investigated using scanning electron microscopy, gel permeation chromatography, X-ray diffraction, Fourier transform infrared spectroscopy, gas chromatography with mass spectrometer, one-dimensional and two-dimensional nuclear magnetic resonance. The results indicated that the lyophilized GP1A was a homogeneous polysaccharide with a low molecular weight of 1.03 kDa. The dominating monosaccharides of GP1A were d-glucose, d-galactose, d-mannose, d-xylose and d-arabinose. The structure analysis indicated the main chain residues sequence of GP1A was α-d-Glcp-(6→3)-α-d-Galp-(1→1)-α-d-Glcp-(3→4)-β-d-Manp-(2→2)-β-d-Arap with branch chains of α-d-Glcp substituted at α-d-Galp and β-d-Xylp substituted at β-d-Manp.