Abstract: Using a planstic rain shelter to keep off precipitation, the relation of main characters and yield of sweet corn cultivars was conducted under different water stress treatments by controlled irrigation. The results showed that drought tolerance coefficients of plant height，stalk diameter，the interval of anthesis and silking (ASI), ear diameter, number of per spike and 1000-grain weight can be used indexs of drought tolerance identification of sweet corn under light water stress，while area of ear leaf, ASI, ear diameter, number of per spike, grain yield rate and 1000-grain weight determined on drought tolerance coefficient of yield under mild water stress. Drought tolerance coefficients of ASI, ear diameter, number of per spike and 1000-grain weight were a set of important indexs for drought tolerance identification of sweet corn cultivars under different water stress. In addition, plant morphological characters such as the plant height, stalk diameter and area of ear leaf, also related with drought tolerance of sweet corn.