Abstract: In this paper, the meteorological grading indices of water-saving irrigation for winter wheat at its different development stages were built, based on the principle of cropland water balance and the theories of insufficient irrigation and regulated deficit irrigation, and by using the multidimensional information, including the daybyday meteorological data in 1961-2008 from 560 meteorological stations, the every ten-day soil moisture data in 1993-2008 from 463 agro-meteorological stations (of which, the data in 1980-2008 came from 84 agrometeorological stations), and the yearbyyear irrigation amount and yield data. In combination with the product-water function (FAO-1979), the relationships of the water deficiency rate and water deficit quantity of winter wheat at the stages of sowingjointing, jointingheading, and heading-maturing and in the whole growth period with yield reduction rate were analyzed. During the whole growth period of winter wheat, the water-saving irrigation meteorological grading indices from I to Ⅲ levels of water deficiency rate and water deficit quantity (secondary indicator) were [15%, 30%), [30%, 50%), and ≥50%, corresponding to 1-2 irrigations (600 m³·hm^-2 each time), 2-4 irrigations, and >4 irrigations, respectively. At sowingjointing stage, the indices were [20%, 40%), [40%, 60%) and ≥60%, corresponding to 1 irrigation, 1-2 irrigations, and >2 irrigations; at jointing-heading stage, the indices were [15%, 30%), [30%, 45%) and ≥45%, corresponding to 0.5 irrigation, 1 irrigation, and >1 irrigation; and at heading-maturing stage, the indices were \[15%, 30%), \[30%, 50%) and ≥50%, corresponding to 1 irrigation, 1-2 irrigations, and >2 irrigations, respectively. These indices could supply scientific support for the optimization of irrigation, and give guidance to agricultural production

Key words: soybean, intercropping, lodging resistance, cellulose, sugar, enzyme activity.