Agricultural water management due to its dominant share in water consumption has the most effective in enhancing water use efficiency in cases droughty and it has reduce economic and social losses. In current study, using genetic algorithms under various weather conditions optimal cropping pattern and scheduling irrigation water of land Marvdasht city covered Doroudzan dam (Fars province). To find the best response from GA in this study the number of generations of 300, population size of 300, probability of crossover of 0.6 and adoptive probability of mutation was considered. By considering to various in probability in rainfall, inflow to dam and evapotranspiration, four weather conditions were determined. Results showed that in hot and dry weather condition no feasible solution existed. At all weather conditions the area for Wheat (winter crops) is greater than other winter crops Also, the area for corn (summer crops) is greater than sugar beet (summer crops). The model indicated that for maintenance all of the cultivation, deficit irrigation contain to achieve greater benefits for the region. According to the findings, at dry weather condition the due to reduce volume of the dam water level in the summer season, limited the cultivated areas of water intensive crops and replace them with crops that need less irrigation water and also irrigation water price reform in order to adjust water demand is recommended.