Poly(N-isopropylacrylamide)(PNIPAM) hydrogels were separately synthesized by microwave irradiation and water-bath heating with water as media,using N,N-methylene-bisacylamide(Bis) as cross-linking agent.Influence of cross-linking agent,reaction temperature and reaction time on the yield was investigated.The temperature and pH sensitivity were tested respectively.The results show that microwave irradiation can greatly shorten reaction time from 10 hours to 1 hour in comparison with water-bath heating,and obviously improve the yield.Extending of reaction time and enhancing of reaction temperature are benefit to improve the yield.The optimum reaction conditions of microwave irradiation are as follows: water as solvent,reaction temperature 100 ℃～110 ℃,reaction time 40 min～60 min,m(Bis)/m(NIPAM)=5/100,97%～98% of the yields can be obtained. Microwave irradiation also improves the temperature-and pH-responsibility of the hydrogels.