Climate change will have important implications in water shore regions, such as Huang-Huai-Hai (3H) plain, where expected warmer and drier conditions might augment crop water demand. Sensitivity analysis is important in understanding the relative importance of climatic variables to the variation in reference evapotranspiration (ET0). In this study, the 51-yrET0 during winter wheat and summer maize growing season were calculated from a data set of daily climate variables in 40 meteorological stations. Sensitivity maps for key climate variables were estimated according to Kriging method and the spatial pattern of sensitivity coefifcients for these key variables was plotted. In addition, the slopes of the linear regression lines for sensitivity coefifcients were obtained. Results showed thatET0 during winter wheat growing season accounted for the largest proportion of annualET0, due to its long phenological days, whileET0 was detected to decrease signiifcantly with the magnitude of 0.5 mmyr-1 in summer maize growing season. Solar radiation is considered to be the most sensitive and primarily controlling variable for negative trend inET0 for summer maize season, and higher sensitive coefifcient value ofET0 to solar radiation and temperature were detected in east part and southwest part of 3H plain respectively. Relative humidity was demonstrated as the most sensitive factor forET0 in winter wheat growing season and declining relativity humidity also primarily controlled a negative trend inET0, furthermore the sensitivity coefifcient to relative humidity increased from west to southeast. The eight sensitivity centrals were all found located in Shandong Province. TheseET0 along with its sensitivity maps under winter wheat-summer maize rotation system can be applied to predict the agricultural water demand and will assist water resources planning and management for this region.