Abstract: Polysaccharide of Elaeagnusangustifolia L. ( EAP) was extracted by hot water.And EAP-1a was made by investiguted deproteinization with sevage method, ethanol precipitation, centrifugation, diasylis, DEAE- cellouse 52 and Sephadex G- 100, concentration and lyophilization. Meanwhile, the composition, content and structure of EAP-1a was investigated through phenol- sulfuric acid method, UV, IR, gas chromatography ( GC) , Congo- red test, NMR and AFM. The results showed that, EAP- 1a was mainly composed of rhamnose, arabinose, xylose, mannose, glucose and galactose with a molar ratio of 0.029∶0.74∶0.51∶0.039∶1.0∶5.19.The molecular weight of EAP-1a was 61421u; IR spectra and NMR showed EAP- 1a had α- glucose which was structural characteristic of the polysaccharide.AFM showed EAP-1a had long chain, which could be winded rod- shaped nano aggregation and no triple helix conformation.