Abstract: This study describes the relationship of irrigation water application, water stress, CWSI and crop yield for the spring corn, hybrid SC704. Irrigation was scheduled using accumulative pan evaporation. Five treatments including 50, 70, 90, 110 and 130 mm based on the accumulative pan evaporation were used as the main plots. Crop Water Stress Indexes (CWSI) were calculated using two different methods described by Idso and Jackson in the literature. A good linear equation was developed using the least square method between the grain yield and the crop water stress index (Jackson method) in the form of Ys = -10.295CWSIj+13.196 with a correlation coefficient of R2 = 0.97. Another equation was also developed, in which the relative humidity, the net receiving solar radiation, the depleted soil moisture from the root zone and the wind speed were related to the canopy-air temperature difference.