Abstract: Based on the network researches of the relationship between water cycle and crop productivity of agro-ecosystem in different ecological type regions in China,the water requirement and consumption characteristics of some crops (wheat,corn,soybean,etc.),crop water use efficiency(WUE) and the crop-water productivity function were investigated.The results showed that there were great improvements in relationship between water and crops in different optimized agro-ecosystem models.The water used by crops was saved,yield and water use efficiency of crops were increased.