ObjectiveThe therapeutic effect of polysaccharides from Zanthoxyli Pericarpium on Alzheimer's disease（AD） was evaluated through establishing a mouse model of AD， and the structural characteristics of the polysaccharides was analyzed by sugar spectrum. MethodThe AD model of mice with rapid aging was established by intraperitoneal injection of D-galactose combined with gavage of aluminum trichloride， and the learning and memory ability of mice was evaluated by Morris water maze test， the histopathological status of brain and neuronal damage were observed by hematoxylin-eosin（HE） staining and Nissl staining. After hydrolysis of polysaccharides from Zanthoxyli Pericarpium with acid and different glycosidases， the characteristics of hydrolysates were analyzed by high performance thin layer chromatography（HPTLC） and fluorescence assisted carbohydrate gel electrophoresis（PACE）. HPTLC chromatography was performed on a silica gel 60 plate with sampling volume of 5 μL， developing solvent of ethyl acetate-glacial acetic acid-water（2∶2∶1）， developing twice， aniline-diphenylamine-phosphoric acid solution as chromogenic agent， and heating at 105 ℃ for 10 min， and then observed under sunlight. PACE experimental conditions were 34% separation gel and 8% concentration gel， electrophoresis buffer was 0.1 mol·L^-1 tris（hydroxymethyl） aminomethane（Tris）-boric acid buffer（pH 8.2）. Electrophoresis was carried out at 0 ℃ and the loading amount was 3-6 μL. The sample ran to the front of the gel with a constant current of 15 mA， and imaged under ultraviolet 365 nm. ResultThe results of Morris water maze test showed that polysaccharides from Zanthoxyli Pericarpium significantly improved the learning and memory ability of AD model mice， shortened the escape latency， and significantly increased the number of crossing and the residence time in the target quadrant. The results of histopathological experiments showed that polysaccharides from Zanthoxyli Pericarpium could improve the pathological conditions and neuronal damage in the CA1 and CA3 regions of hippocampus of AD mice， and the number of Nissl corpuscles was significantly increased. The results of sugar spectrum analysis showed that the results of HPTLC and PACE analysis were basically consistent， polysaccharides from Zanthoxyli Pericarpium could be mainly hydrolyzed into small molecular sugars by cellulase and pectinase， indicating that they mainly contained β-1，4-glucosidic bond and α-1，4-galacturonic acid glycosidic bond， and could be slightly hydrolyzed by glucanase， β-galactosidase and β-mannase， indicating that they contained only a small amount of α-1，6-glucosidic bond， β-galactosidic bond， β-1，4-mannosidic bond. ConclusionPolysaccharides from Zanthoxyli Pericarpium has obvious therapeutic effect on AD mice， and its structure mainly contains β-1，4-glucosidic bond and α-1，4-galacturonic acid glycosidic bond， which can provide a reference for the structural analysis of traditional Chinese medicine polysaccharides.