Objective:The high performance liquid chromatography (HPLC) method of precolumn derivatization with 1-phenyl-3-methyl-5-pyranozolone (PMP) was developed to efficiently separate several monosaccharides. And the monosaccharide composition and content of polysaccharides in the medicine pair of Dioscorea opposita and Rehmannia glutinosa and their single herb medicine were determined and compared. Method: A Hypersil ODS2 column with the mobile phase of 0.05 mol·L-1phosphate buffer (pH 6.7)-acetonitrile (83∶17) at the detection wavelength of 254 nm was used. The flow rate was 1 mL·min-1

the column temperature was kept at 30 ℃. Result: All three polysaccharides contained mannose

rhamnose

glucuronide acid

glucose

galactose and arabinose. However

fucose was not detected. At the same time

it was found that the content of mannose

rhamnose

glucuronide acid

glucose

galactose and arabinose in their medicine pair was between in the single Dioscorea opposita polysaccharides and Rehmannia glutinosa polysaccharides. Conclusion: The developed method is simple

rapid and accurate. Therefore

it is an efficient method to analyze the monosaccharide composition in different kinds of polysaccharides in drug and food.