A high performance liquid chromatography (HPLC) method for the determination of the monosaccharide compositions and molar ratio of polysaccharide in quince has been established. The quince polysaccharides were derivatized with 1-phenyl-3-methyl-5- pyrazolone (PMP) after hydrolyzed into monosaccharides with 2 M sulfuric acid. Monosaccharide derivatives were separated by a reversed phase C18 column and monitored by UV at 250 nm. Analysis of monosaccharides of quince polysaccharides sample by HPLC indicated the presence of mannose, rhamnose, glucose, galactose, and arabinose with the molar ratio of 0.10, 0.72, 1.12, 4.23, and 4.73, respectively. It could be applied for the quality control of quince polysaccharides. Moreover, quince polysaccharide shows the inhibitory activity of protein tyrosine phosphatase- 1B (PTP1B) with IC50 value of 2.07 μg/mL.