The virtual water flows could be seen as the spatial redistribution of water resources in virtual form, which have a significant influence on regional economy and water resources. The production, consumption, transfer of grain crops, water use and virtual water flows were calculated for different provinces of China in 2010. Then the effects of regional grain virtual water flows on regional economy and water resources were demonstrated by using water saving amount, water stress index and GDP per capita. The results showed that the volume of grain virtual water flows between different provinces of China was 113.81 Gm3 and the blue water was 44.97 Gm3. Most of the flows were from regions with relatively high water use efficiency to those with relatively low water use efficiency regions, from water-shortage regions to water-rich regions, from regions with low economic level to those with high economic level regions. As a result, about 57.89 Gm3 of water resources were saved due to regional grain virtual water flows and the value for blue water was 47.89 Gm3, the water stress index increased from 1.61 to 2.04 assuming the virtual water export was zero, and the GDP per capita decreased from 43 428 Yuan to 31 776 Yuan assuming that all of water resources used to produce the exported grain crops could be used for industrial production. The improvement of agricultural water use efficiency, the compensation for virtual water flows and the optimization of cropping pattern could be measures with great significance to alleviate the negative effects caused by regional virtual water flows of China.