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Agriculture in arid areas with inadequate water supply enquires the right cognition of evapotranspiration related to water application. In this research a single-cross hybrid of maize (S.C. 704), under the split plot experiment based on randomized complete block design was selected for cultivation in 2015 and 2016 years. The experimental treatments were set up in three planting dates: 21 st April, 11th May and 31st May, and four irrigation regimes: I-100 (100%), I-80 (80%), I-60 (60%) and I-40 (40%) of the estimated evapotranspiration (ET). The results showed a drastic reduction by 44 to 49% in grain yield under low irrigation regime (I-40) compared with full irrigation regime (I-100), respectively. Irrigation water use efficiency based on grain yield (1.39 and 1.20 kg/m(3)) and biological yield (4.79 and 4.53 kg/m(3)) was the highest in I-40 for each year, respectively. Corns planted earlier fulfilled silking-maturity duration faster than corns planted at the end of planting window as a result of reducing final yield potential. Under drought stress situation of this experiment it was shown that with long season hybrid, grain yield and irrigation efficiency can be improved by timely applications of planting dates and irrigation levels.