Using the mesoscale model the macro physical characteristics of cloud were calculated. According to the analysis on effects of precipitation for yield in the different periods during plant growth stage and their variation characteristics, the dynamic effects of plant economic benefit per mm precipitation for different regions were obtained. The decision-making method for choosing operation area of optimal economic benefit ware proposed by using the macro-indices of ice-saturation, vertical transportation of water vapor and vapor integral and indices of potential economic benefit of precipitation enhancement for main plants in the different growth stages. The decision-making process of choosing operation time, height and area were carried out in the artificial precipitation operation technique system of Shandong Province.