The present invention provides a method for manufacturing polysaccharides isolated from Curcuma xanthorrhiza, including steps of: (S1) preparing a powder of Curcuma xanthorrhiza Roxb.; (S2) extracting the powder with an organic solvent, and then filtering or centrifuging to obtain a residue; (S3) extracting the residue to prepare a solution containing polysaccharides; (S4) removing starch by adding starch-hydrolyzing enzyme to the polysaccharides-containing solution; (S5) precipitating the polysaccharides after the step (S4); and (S6) purifying the polysaccharides after the step (S5), polysaccharides obtained according to the manufacturing method, and a pharmaceutical composition in eluding the polysaccharides as effective component. The polysaccharides according to the present invention may be very effectively used in drugs and functional foods for stimulating macrophage activity, preventing and treating immunological diseases including cancer, and enhancing immunity after the treatment of the immunological diseases.