The analysis of climate change and its effect on the soil moisture of grasslands has great significance to the understanding of the reasons for grassland degradation and the recovering of the grassland ecosystem.Based on the 40year climate data and 20-year observational data of soil moisture,the climate change trend and its effect on soil moisture over the Inner Mongolia typical steppe are analyzed by using the linear trend method,etc.The results show that the 40-year climate change trend over the Inner Mongolia typical steppe is similar with that of the global climate;the main factors influencing soil moisture are precipitation and evaporation,but air temperature influences indirectly the soil moisture through affecting evaporation.The difference between evaporation and precipitation is a direct index for analyzing the effect of climate change on soil moisture.Climate warming results in the increase of water evaporation,and thus accelerates the drying rate of soil under the condition of insignificant precipitation increase.