Based on the 18-year experimental data of water consumption of rice, the relation was analyzed between water consumption and main meteorological factors, such as light, temperature and water. Regarding to the weather type in the near future as well as the characteristics of rice soil, the sum of water irrigation can be determined. Not only can it meet the physiological needs of water, but also decrease the sum of requirement of water. Also, water can be saved, the cost of agriculture reduced and a high yield approached.