Abstract: OBJECTIVE To optimize the derivative method reasonably and detect monosaccharide components and molar ratio of taraxacum polysaccharides. METHODS Pre-column derivative reagent was 1-phenyl-3-methyl-5-pyrazolone(PMP), monosaccharide composition and molar ratio of taraxacum polysaccharides were detected by reversed-phase high performance liquid chromatography (RP-HPLC). Chromatographic conditions: ZORBAX-C18 column; mobile phase: 0.1 mol·L^-1 phosphate buffer solution (pH 6.7)-acetonitrile (83∶17); velocity: 1 mL·min^-1; detection wavelength: 245 nm; injection volume: 20 μL; column temperature: room temperature. RESULTS Taraxacum polysaccharides was composed of D-rhamnose, glucose, D-galactose D-xylose, D-Arabinose. The molar ratio of taraxacum polysaccharides which was extracted by different means was as forrows: water extraction method, Rha∶Glc∶Gal∶Ara=0.088∶0.500∶0.190∶0.340; ultrasonic extraction method, Rha∶Glc∶Gal∶Ara=0.050∶0.350∶0.080∶0.320; cellulose extraction method, Rha∶Glc∶Gal∶Ara=0.270∶0.630∶0.330∶ 0.460; synergistic ultrasonic extraction and cellulose extraction, Rha∶Glc∶Gal∶Ara=0.078∶0.550∶0.130∶0.170. CONCLUSION The improved derivative method and the chromatographic conditions of isocratic elution were simple, rapid and with a good reproducibility, and can be used to detect monosaccharide components and molar ratio of taraxacum polysaccharides.