Abstract: In order to investigate the influence of meteorological conditions on the sunflower water requirement, this study calculated daily water requirement of sunflower in different precipitation years (wet year, normal year, dry year), and analyzed the variation of water demand and source in the process of sunflower growth. The results show that: water demand was different in different growth stages of sunflower, which was small in the early and late stages, biggest in the middle stage, and the drier the year was, the more the water required; Then coupling degree of water requirement and effective precipitation was highest in wet year, normal year taked the second place, followed by dry year. Consumption of soil water was various in different precipitation years, which showed maximum value in dry year. It had little effect on soil water in the early growth season, and greater influence from blossom to mature of later stage.