Cutting central and lower parts of maize leaives to make the leaf area index(LAI) range among 4.5 to 7.0,to study the effects of leaf cutting treatment to maize yield under the high plant population cultivation condition.The results showed that all the yields of treatments were higher than CK,the highest yield was LAI 5.5 treatment.Put the LAI 5.5 as the model,the more the number of the LAI to the model,the lower the yield.The harvest ears was more along as the LAI was less.The most kernel of ear is the treatment LAI 5.5.The weight of 100 kernel was not signifisant difference on all treatments.