OBJECTIVE：To analyze and compare th e contents of 6 kinds of monosaccharide in Astragalus membranaceus from different growth years . METHODS ：2-4 years old A. membranaceus from three areas were extracted with water extraction and alcohol precipitation ，Sevage deproteinization to obtain A. membranaceus polysaccharide. The samples were firstly hydrolyzed with trifluoroacetic acid （TFA）and then derivatized by 1-phenyl-3-methyl-5-pyrazolone（PMP）. HPLC analysis was adopted to determine the contents of 6 kinds of monosaccharide as mannose ，rhamnose，galacturonic acid ，glucose，galactose，arabinose. The determination was performed on Symmetry C 18 column with phosphate buffer solution （pH 6.8）-acetonitrile（84∶16，V/V）as mobile phase at the flow rate of 1.0 mL/min. The detection wavelength was 245 nm，and column temperature was 35 ℃. The sample size was 20 µL. RESULTS ：The contents of mannose ，rhamnose，galacturonic acid ，glucose，galactose and arabinose were 0.50-0.94， 0.76-1.60，3.35-7.86，87.33-275.77，1.95-8.96，2.35-14.04 mg/g，respectively. Total contents of monosaccharide from 2，3，4 years old A. membranaceus were 98.26-139.92，173.81-295.71，122.37-182.41 mg/g，respectively. There was significant difference in the contents of glucose between 3 old years A. membranaceus and 2，4 old years A. membranaceus （162.71-275.77 mg/g vs. 87.33-107.70，111.54-167.26 mg/g，P＜0.05）. CONCLUSIONS ：Above 6 monosaccharides are detected in 2，3，4 years old A. membranaceus，among which the content of glucose is the highest. The content of glucose in 3 years old A. membranaceus is higher than that in 2 and 4 years old A. membranaceus .