Abstract: Grassland is one of the most important natural resources in China. Investigations on grassland water conservation and its value are urgently needed and are of realistic significance. In present study, combined with the practical situation of grassland ecosystem in Dongwuqi of Inner Mongolia, we studied the evaluation methods on grassland water conservation and its value and assessed their spatial-temporal variations. The results revealed that in this region, the grassland water conservation in the year of2000, 2005 and 2010 were 1.88 ×10~9, 7.63 ×10~8and 2.01 ×10~9m~3, respectively, and the their corresponding value were 1 350 million Yuan, 547 million Yuan and 1 440 million Yuan, respectively. During the period from 2000 to 2005, the total value of grassland water conservation in Dongwuqi reduced by 59.48%. However, during the period from 2005 to 2010, the grassland water conservation in this region increased by 163.25%.