Growth status and some physiological indexes of seedling of Zea mays ‘Zhengdan 958’ were analyzed under high temperature （34 ℃， 38 ℃， and 42 ℃） stress by taking （25±4） ℃ as the control. The results show that with increasing of treatment temperature， plant height， main root length， root／shoot ratio， and fresh weight per plant of seedling gradually decrease， while leaf area per plant gradually increases； SOD activity， POD activity， O2^-_· production rate， proline content and MDA content in leaf and root， and soluble protein content in leaf gradually increase， while soluble sugar content in leaf and root and soluble protein content in root gradually decrease. Overall， growth indexes and most physiological indexes of seedling under high temperature stress of 42 ℃ show significant differences （P＜0.05） with those of the control group. Seedling of Z. mays ‘Zhengdan 958’ can enhance its tolerance under high temperature stress mainly by reducing the growth， increasing POD activity in root and proline and soluble protein contents in leaf.