Abstract: Soil evaporation is an important component of water consumption in farmland. In this paper, the soil evaporation in field ditch and on ridge was measured by using two kinds of micro-lysimeters respectively, the change law of soil evaporation and crop transpiration in summer maize under furrow irrigation was studied, and the relationship between relative soil evaporation intensity and soil water content as well as the relationship between soil evaporation intensity and leaf area index was analyzed. The results showed that soil evaporation in summer maize field under furrow irrigation condition accounted for 33.06%～34.35% of water consumption in the whole growth period, and there was a good exponential function relationship between relative soil evaporation intensity and surface soil water content as well as leaf area index. Soil evaporation intensity was comparatively great within 2～3 days after an irrigation or rainfall, and it was influenced by atmosphere evaporation intensity obviously. Therefore, to reduce wetting area and wetting times of surface soil is the major technical way and measure to decrease soil evaporation and to raise crop water use efficiency if crop transpiration is not influenced.