The purpose of this study is to determine the evapotranspiration in Fars province that in many studies such as hydrological balance of water, irrigation systems design and management, simulation of product volume and management of water resources is very important. To do this, first, required data such as daily temperature, humidity, precipitation, wind speed, solar radiation pressures, solar radiation, etc. was collected. We used 12 stations with the same statistical interval, for the period 1995-2015. In order to estimate the evapotranspiration of the reference plant in different growth stages, Torent White, Penman-Monteith and Hargreaves-Samani methods were used. Results showed that with decreasing latitude, the evapotranspiration rate increased, and the highest rate of evapotranspiration occurs in the south, southeast and the center of the study area. The correlation coefficient R2 between height and White Penman, Monteith and Hargreaves Samani, are 0.9135, 0.53223 and 0.5286 respectively.
