Abstract: Potential evapotranspiration (ET₀) is a key to estimate crop water requirements and base to make irrigation schedule. Sensitivity analysis is crucial in assessing the impact of climatic variables on ET₀ estimations. In this study, observed daily climatic data from 1961 to 2011 at four meteorological stations located in Jinghuiqu Irrigation District were used. Daily ET₀ was estimated with the FAO-56 Penman-Monteith equation. The trends in climate variables were detected by using Mann-Kendall test. A non- dimensional relative sensitivity coefficient was employed to predict responses of ET₀ to four climatic variables. Sensitivity and relative variation rate of climate variables were used to attribute ET₀ variation. The results showed that statistically significant decreasing trends in wind and daily sunshine duration and significant increasing trends in air temperature were observed. Relative humidity has a significant decreasing trend in the southern and southeastern irrigation districts and an insignificant increasing trend in the western and northeastern irrigation districts. Mean daily sensitivity coefficients for relative humidity, solar radiation, wind speed and air temperature in the district were -0.77, 0.41, 0.16 and 0.08, respectively. In general, relative humidity was the most sensitive variable, followed by solar radiation, wind speed and air temperature. The change of ET₀ is primarily attributed to the significant decrease of wind and solar radiation.