Macroporous temperature-sensitive poly(N-isopropylacrylamide) (PNIPAAm) hydrogels have beensuccessfully synthesized by using poly(ethylene glycol) (PEG) as the pore-forming agent. Scanning electronmicroscope graphs reveal that the macroporous network structure of the hydrogels can be adjusted byapplying different molecular weights of PEG during the polymerization reaction. The surface roughnessof the hydrogels is also investigated using atomic force microscopy, and the results indicate that the surfaceof the PEG-modified gel is much rougher compared to that of the conventional PNIPAAm gel. The newlyinvented macroporous hydrogels exhibit much better properties as temperature-sensitive intelligentpolymers. For instance, at a temperature below the lower critical solution temperature (LCST), theyabsorb larger amounts of water and show obviously higher equilibrated swelling ratios in the aqueousmedium. Particularly, due to their unique macroporous structure, the PEG-modified hydrogels show atremendously faster response to the external temperature changes during deswelling and reswellingprocesses as the temperature cycles across the LCST. They can also shrink and lose water with dramaticallyrapid rates at temperatures above the LCST. The macroporous PNIPAAm gel has potential applicationsin controlled release of macromolecular active agents.Macroporous temperature-sensitive poly(N-isopropylacrylamide) (PNIPAAm) hydrogels have beensuccessfully synthesized by using poly(ethylene glycol) (PEG) as the pore-forming agent. Scanning electronmicroscope graphs reveal that the macroporous network structure of the hydrogels can be adjusted byapplying different molecular weights of PEG during the polymerization reaction. The surface roughnessof the hydrogels is also investigated using atomic force microscopy, and the results indicate that the surfaceof the PEG-modified gel is much rougher compared to that of the conventional PNIPAAm gel. The newlyinvented macroporous hydrogels exhibit much better properties as temperature-sensitive intelligentpolymers. For instance, at a temperature below the lower critical solution temperature (LCST), theyabsorb larger amounts of water and show obviously higher equilibrated swelling ratios in the aqueousmedium. Particularly, due to their unique macroporous structure, the PEG-modified hydrogels show atremendously faster response to the external temperature changes during deswelling and reswellingprocesses as the temperature cycles across the LCST. They can also shrink and lose water with dramaticallyrapid rates at temperatures above the LCST. The macroporous PNIPAAm gel has potential applicationsin controlled release of macromolecular active agents.