A novel composite hydrogel was prepared via uv irradiation copolymerization of acrylic acid and maize bran in the presence of composite initiator (2,2-dimethoxy-2-phenylacetophenone and ammonium persulfate) and cross-linker (N,N'-methylenebis (acrylamide)). under the optimized conditions,maize bran-poly (acrylic acid) was obtained (2507 gg-1 in distilled water and 658 gg-1 in 0.9 wt% Nacl solution).effects of granularity,salt concentration, and various cations and anions on water absorbency were investigated.it was found that swelling was extremly sensitive to the ionic strength and cation and anion type. Swelling kinetics and water diffusion mechanism in distilled water were also discussed.moreover, the products showed excellent water retention capability under the condition of high temperature or high pressure. The salt sensitivity, good water absorbency, and excellent water retention capability of the hydrogels give this intelligentized polymer wide potential applications.