Abstract: The sulfonated gelatin hydrogels were obtained using gelatin as material and glycidyl methacrylate and NaHSO₃ as modifier.Then,sulfonic acid groups were covalently immobilized onto gelatin.The chemical component and structure of the hydrogels were verified by Fourier Transform Infrared Spectra (FT-IR),X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microstructures (SEM).The dynamic viscoelastic spectrometer was used to investigate the storage modulus.The electric-field responses of the hydrogels under different external electric fields were disscussed.Results showed that the electric-field response was enhanced under an external applied electric-field with the increasing percentage of S atom in sulfonated-gelatin hydrogel.When the applied electric-field was 1.6 kV/mm and the percentage of S atom in sulfonated gelatin hydrogels was 1.59%,the hydrogels had the strongest response and the storage modulus increment sensitivity was up to 31.86%.