In order to study the electric field sensitive of cation character DMDAAC hydrogels, Acrylamide/Dimethyldiallylammonium chloride (AM/DMDAAC) hydrogels are prepared by free radical copolymerization in aqueous solution in the presence of N,N methylene bis (acrylamide) (MBAAm) as the crosslink agent, ammonium per sulfate and sodium bisulfite as the redox initiator. Deswelling kinetics and bending behaviors of the sample hydrogels under electric stimulus are illustrated. It is found that monomer amount of DMDAAC, the time as well as the size of applied voltage, and the ion intensity of solution have a favorable impact on the electric sensitive properties of the AM/DMDAAC hydrogels. It might have applications in chemical valve and bionic actuator. Hydrogels display a bending toward anode in NaCl solution of low chroma. The bending toward anode is depressing along with NaCl chroma increasing. Hydrogels show a bending toward cathode in NaCl solution of high chroma. The banding angle of hydrogels is affected by the critical chroma of NaCl from 0.3% to 0.4%. Since these hydrogels are made up of different monomer content, the critical chroma of NaCl is also different.