Based on the water footprint method, this paper constructs the matching index of water resources and grain production, and analyses the dynamic evolution characteristics of water consumption for grain production from three aspects: total water consumption, source structure and matching relationship between grain and water. Then use Logarithmic Mean Divisia Index method to decompose the change of water consumption in grain production into nine kinds of effects. The results show that: water footprint for grain production experienced three stages: a small decline, a rapid recovery and a steady rise in 2002-2017. The grain production of food production is poorly matched and the contradictions tend to intensify. From the perspective of decomposition effect, the structural adjustment of the third-generation and the progress of water-saving technology are the main factors to reduce the water consumption in grain production; however, the relevant policies of water-saving in agriculture and the adjustment of planting structure have not brought the expected water-saving effect into full play; the matching relationship between grain and water is deteriorating, and water is also in the primary Lack of soil resources and poor matching between them are not conducive to restraining the increase of water use.