The best is to read these instructions and follow the outline of this text. Thermo-sensitive hydrogels based on linear HPMC and cross-linked PNIPAAm were prepared by the semi-IPN technique. The interior morphology of hydrogels was investigated by fluorescent microscope. The hydrogels were characterized by Fourier transform infrared (FTIR). The thermo-sensitivity, equilibrium swelling rate and swelling dynamics of these hydrogels were investigated. The chemical compositions and structures of the semi-hydrogels were similar to each other, as measured by FTIR. The results indicated that the swelling ratio of the hydrogel decreased with increasing temperature. In pH 7.4 buffer solution (37°C ), when the weight ratio of HPMC to NIPAAm was 1/100, the swelling ratio was the maximum. In comparision with a conventional PNIPA hydrogel, the semi-IPN hydrogel synthesized with hydroxypropyl-methyl cellulose exhibits a much faster response rate to temperature changes. For example, PNI-H05 loses 87% water within 5min, whereas the conventional hydrogel loses only about 25% water within 5 min. and about 50% water within 50 min.