The study aims to optimize the extraction process of Curcumae Rhizoma polysaccharide(CRP) and investigate their structure and effects on improving functional constipation.With the yield of polysaccharide as the index,the best extraction process of CRP was optimized by single factor test and response surface method.Meanwhile,CRP were purified by cellulose column to obtain homopolysaccharides,and their structures were further characterized by UV,IR and scanning electron microscopy (SEM),and the compositions of monosaccharides were analyzed.Forty-eight SD rats were randomly divided into six groups,which were control group,model group,positive drug group (mosapride),CRP in high dose group (400 mg/kg),CRP in medium dose group (200 mg/kg) and CRP in low dose group (100 mg/kg).Loperamide hydrochloride was used to replicate the rat model of functional constipation,and the improvement of CRP was investigated.The results indicated that the optimal extraction process optimized by response surface method was extraction temperature 100 ℃,extraction time 66 min,and liquid ratio 1∶24 (g/mL).One neutral polysaccharide and three acidic polysaccharides were isolated and purified from CRP.Their structures were analyzed by UV,IR and SEM,and the monosaccharide compositions were also analyzed.The results of the functional constipation showed that CRP in high dose group improved the shape,weight and humidity of stool,significantly reduced the number of residual feces in colon,significantly increased the propulsion rate of small intestine,gastrin and motilin contents,and significantly improved the pathology of colon.The studies could provided a theoretical basis for the development of CRP and its application in the treatment of functional constipation.