Evaluation of soil water balance response to climate change is one of the most important aspects of assessing climate change impact on agricultural production under the background of global change. A new empirical approach was used to downscale GCM grid output, and three emissions scenarios (A2a, B2a and GGal) of Wangdonggou watershed during 2010-2039 were developed to simulate the potential change of soil water balance (soil moisture, evaporation, percolation and crop transpiration) with the WEPP model. HadCM3 predicted a 1.8%-7.5% increase in annual precipitation, 0.5-0.9 ℃ rises in maximum temperature, and 2.0-2.3 ℃ rise in minimum temperature for the station. Compared with the present climate, plant transpiration would mainly change from April to June and soil evaporation from July to September. Percent increases under climate changes, as averaged for each emissions scenario and slope, ranged -5%-19% for crop transpiration, -4%-4% for soil moisture, -7%-7% for soil evaporation, 6.5%-44.1% for wheat grain yield, 26.3%-41.7% for maize yield. Predicted soil water percolation change was the greatest under A2a, the least under GGal, and intermediate under B2a. These results suggest that change of climate and crop growth will influence soil water balance significantly.