Objective To study the effect of high humid and warm environment on the central nervous system and the changes of expression of glutamate (Glu) and NmethylDasparate receptors 2 (NMDAR2) in rat hypothalamus. Methods The experimental rats were put into a simulated climate cabin (with the dry ball temperature of (400±05)℃ and relative humidity of (60±5)%. Behavioral responses of the rats were observed on the time. The rats that displayed a twitch or coma were taken out of the cabin. By using immunohistochemical ABC methods, we observed the expression of Glu, NMDAR2 and Vasopressin(VP) in the paraventricular nucleus(PVN) and supraoptic nucleus (SON). Results The animals showed restlessness and agitation; their breath frequency increased; they scratched the face with the forelimbs and some animals died in 120 minutes. The expression of Glu, NMDAR2 and VP in PVN and SON were significantly increased in the high humid heat stimulation group as compared with control group (P<0.01). Conclusion The ultimate endurance of rats to survive in a high humid and warm enviroment lasts about 120 minutes. The glutamate in hypothalamus migh