Abstract: With the increases of world trade a new concept,virtual water,recently arising and being frequently used in the field of water resource has became an important factor affecting region water system.The Economic background of the appearance of its appearance is analyzed,and methods to calculate the content of virtual water in crops and livestocks and the virtual water flow are introduced and reviewed.The virtual water flow concerning China's crop trade is also analyzed preliminary.And the importance of virtual water in raising the water use efficiency,making the comprehensive water resource planning,and possible effect on social and economic aspects are concluded preliminarily.