In order to investigate the grain yield, one hundred grain weight, stress tolerance index (STI), concentration of chlorophyll (a+b), the amount of proline and soluble sugar of maize hybrids in response to drought tension, the present experiment was carried out as split plots based on randomized complete blocks design with four replications on the farm of Moghan Research Station, during 2010 and 2011. The main factor irrigation at two levels (normal irrigation and irrigation cut at grain filling stage) and sub factor were maize hybrids (Single Cross700, Single Cross KLM and Single Cross704). Combined analysis of data showed that drought tension had a significant effect on all traits. The drought tension reduced 32.67 percent the amount of grain yield, 18.59 percent one-hundred grain weight and 15.71 percent concentration of chlorophyll (a+b); but, drought tension increased 88.77 percent the amount of proline and 45.51 percent of soluble sugar content. The amount of STI in related to Single Cross 704, Single Cross KLM and Single Cross 700 were 1.01, 0.70 and 0.50, respectively. Single Cross 704 displayed the maximum amount of grain yield, one hundred grain weight, concentration of chlorophyll (a+b), the amount of proline and the minimum amount of soluble sugar was related to Single Cross 704. According to the obtaining results, Single Cross 704, Single Cross KLM and Single Cross 700 were studied and identified as tolerant, semi-tolerant and sensitive to drought tension, respectively.