Hemicellulosic polysaccharides were isolated from the raw and steam-exploded Lespedeza crytobytrya stalks by sequential l M NaOH extraction and fractionated into Hemi-a and Hemi-b fractions by acidification and ethanol precipitation, respectively. The Hemi-a fractions had relatively lower molecular weights and took up 84.6-95.5% of the total released hemicelluloses. After steam explosion, both hemicellulosic fractions were obviously degraded, and a certain amount of glucose or oligosaccharides derived from the amorphous cellulose was coisolated. The influence of increasing incubation time from 2 to 10 min is further discussed, based on the physicochemical properties of the obtained hemicelluloses characterized in terms of sugar component, gel permeation chromatography (GPC), thermal stability, and C-13 NMR spectroscopy analysis.