The laws of water consumption in c, peanuts and millet on the semi-drought area of west Liaoning Province werernstudied through the FAO-Penman Monteith method and the water balance method. Among three corps, the amount of the day waterrndemand, the whole growth period water demand and the soil water defi cit of c were all the largest. At the same time, its degreernof agreement between the water demand and the level of precipitation was the worst, and its average in crop coeffi cient was larger.rnThe amount of the day water demand, the soil water defi cit and its average in crop coeffi cient of millet were larger. Because of itsrnshort growth period, the whole millet growth period water demand was the least, resulting in its degree of agreement between thernwater demand and the level of precipitation was better. For peanuts, the amount of the day water demand, the soil water defi cit andrnits average in crop coeffi cient were both the least, the whole growth period water demand was less, degree of agreement between thernwater demand and the level of precipitation was better, the average in crop coeffi cient was less, the change of crop coeffi cient wasrnrelatively steady, and water demand in the early and middle period of crop growth was less. From water use effi ciency, crop plantrnorder of regional priorities should be c, millet, and peanuts. From economic benefi ts of water, crop plant order of regional prioritiesrnshould be peanuts, c, and millet; and crop plant order of priority to irrigation should be peanuts, millet, and c.