A novel pH- and temperature-responsive poly (N-isopropyl acrylamide/itaconic acid/acrylamide)(NIPAM/IA/AM) hydrogel was synthesized by inverse microemulsion polymerization and crosslinker effects on its swelling and gel properties were investigated. Water absorbency and salt solution absorbency increased with crosslinker amount increased to 0.2 wt%, and then decreased, while pH-sensitivity decreased and gel strength, temperature-and shear- resistance increased with increased crosslinker amount. The average particle size of the NIPAM/IA/AM hydrogels synthesized at crosslinker amount of 0.2 and 0.4 wt%, increased from 0.45 and 0.38 mu m to 11.86 and 9.88 mu m, respectively, with swelling time from 1 to 15 h. The NIPAM/IA/AM hydrogel demonstrated shear-thinning behavior and increased gel strength from 25 to 35 A degrees C.