Abstract: The alternative roots-divided irrigation and fixed roots-divided irrigation were used to compare the effects of roots-divided irrigation pretreatment on root vitality and leave water content of maize in this experiment．The results show that the roots-divided irrigation has no marked influence on the relative water content，plasma membrane permeability and vitality of roots．The alternative roots-divided irrigation has better water-containing effects than the fixed roots-divided irrigation．The root vitality and plasma membrane permeability are positively and negatively related to the leave water content，therefore maintaining the root vitality is closely associated with keeping higher leaf water content in maize．