Abstract: The cassava grafted acrylamide was used, and the starch was used as the backbone to graft the acrylamide branch to form a sensitive spatial network macromolecular structure hydrogel. The tapioca starch-based hydrogel with high swelling property was prepared by using cassava starch as raw material, acrylamide as monomer, N, N-methylenebisacrylamide as cross-linking agent and ammonium persulfate as initiator. The tapioca starch-based hydrogel with high swelling property was prepared, and the sensitivity of the hydrogel to temperature and pH was studied. It was characterized by fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), X-ray diffractometry (XRD) and other modern analytical testing methods. The experimental results showed that when the amount of tapioca starch was 1 g, the amount of acrylamide was 5 g, N, N-methylenebisacrylamide was 0.06 g, and ammonium persulfate was 0.03 g, the prepared tapioca starch hydrogel had a high water absorption rate. The characterization results demonstrated that the tapioca starch hydrogel had been successfully prepared. The hydrogel swelling equilibrium ratio changes with temperature and pH change, the swelling property reached maximum at 35℃, and the swelling property reached the highest under the alkaline condition of pH12.24, it was indicated that the prepared hydrogel had both temperature and pH sensitivity. The good swelling property of the hydrogel would be used in the fields of heavy metal ion adsorption, biomedicine, and the application value was high.