Abstract: Using large moving water proof installations, controlling different soil water content strictly by people, a systematic study was conducted to the response of drought on growth of root and shoot of summer maize during the growing period. The results indicate: root growth, shoot growth and the ratio of root/shoot (R/S) get changed, and the growth period becomes longer when water supply is decreased although the general accumulative trend of root and shoot, plant height, stem diameter of summer maize is not affected by drought. The responses of root and shoot to the same water condition are not identical. With the strength of stress, the time of the maximum of root and shoot dry weight, plant height, stem diameter become later compared with the full-water treatment. R/S is changed under the different soil content. Water treatment had the lowest effect on R/S during the flowering stage to the filling stage and the maximal effect on R/S during the jointing stage to the heading stage. R/S of treatment H was 125.77% times as much as treatment L at this period. Under the full-watered treatment, the ratio of R/S is the largest(R/S=0.173),which may be caused by the building of extensive root system. These results suggested that harmonizing the balance of root-shoot under drought stress, playing the role of root and leaf at most could enhance yield.