Abstract: The influence of dietary vitamin E （VE） supplementation on blood biochemical index and laying performance of hens in high temperature environment was investigated in this study. Three hundred and sixty 41\|week\|old healthy laying hens of Jingfen I were divided into 4 groups. Each group had 3 repeats and each repeat had 30 hens. Group I was the control group （basal diet）， group Ⅱ （basal diet+100 mg·kg-1 VE）， group Ⅲ （basal diet+200 mg·kg-1 VE） and group Ⅳ （basal diet+300 mg·kg-1 VE） were treatment groups. The first week was set for an adjustment period， the following six weeks were set for experimental period. The results showed that aspartate transaminase （AST） activity in the control group was significantly lower than those in VE added groups under heat stress （26-33℃， average of 29℃）（P<0.05）， and low density lipoprotein cholesterol （LDLC） and glucose （GLU） contents were significantly higher than those in treatment groups under heat stress （P<0.05）. As for laying performance， feed\|gain ratio and egg laying rate of treatment groups were significantly higher than those of the control group （P<0.05）， among which the treatments of 100-200 mg·kg-1 VE showed the best laying performance. In conclusion， under the condition of heat stress， the egg laying performance of laying hens could be significantly improved when the basal diet was added with 100-200 mg·kg-1 VE， and some biochemical indexes were significantly affected as well.

Key words: heat stress, vitamin E, laying hens, blood biochemical index, laying performance