Water resource is one of the most important input factors in agricultural production. Despite the relative abundance of water resources, China is still considered as a water stressed country with approximately 2100m3 per capita per year. Aiming to construct the evaluation index system to comprehensively evaluate the water use efficiency and find out the problems concerning water as production input factors during the water usage process in Chinas grain production. The superefficiency DEA method was applied to evaluate the water use efficiency within Chinas grain production sector from 2009 to 2014, and to find out the proper adjustment direction and adjustment level. Eventually the countermeasures and suggestions for improving grain production’s water use efficiency in China were put forward. The results showed that there were substantial differences in grain production’s water use efficiency among China’s four major economic zones. The northeast region had performed the highest efficiency level and possessed slightly fluctuate trend simultaneously, while the central and western regions revealed the lower efficiency level and greatly fluctuate trend. Last but not the least, the eastern region with the lowest efficiency level characteristic experienced the declining trait. In addition, there were significant differences in grain production’s water use efficiency among different provinces which was attributed to unreasonable water input allocation within the grain production’s sector; the serious problem of coexistence of water input redundancy and inadequacy phenomena, which precisely reflected the failure in mutual promotion between irrigation system and effective precipitation in China’s grain production sector.