Abstract: Based on four years' investigations the dynamics and patterns of soil moisture in the farmland of Taihang Piedmont were analysed.The soil moisture of top layer was greatly affected by water supply,while in deep layer of the soil,soil water content was keeped at relatively steady statues.Then by increasing crop root growth to increase water uptake from the deep layer of soil would reduce the water stress effects on crop and also the irrigation numbers.Another aspect for reducing irrigation was to reduce soil evaporation from the farmland.During the growth periods of winter wheat and corn there were about total 200mm evaporation from the soil surface.According to our experiments here,straw mulch could reduce this value to 100mm.So this was another effective way for increasing the water use efficiency in the farmland.