【Objective】 This study aimed to analyze temporal and spatial characteristics of reference crop evapotranspiration (ET_0) and predict future ET_0 in Shaanxi so as to provide foundation for the development of crop irrigation system and water resources plan.【Method】 Based on the daily meteorological data from 18 meteorological stations in Shaanxi during 1961-2000,daily ET_0 values were calculated using Penman-Monteith equation recommended by FAO.According to the NCEP reanalysis data and GCMs (HadCM3) output data,statistical downscaling model was used to predict future ET_0 under the A2 and B2 emission scenarios.【Result】 Spatially,ET_0 values in Shaanxi had the increasing trend from south to north during 1961-2000.ET_0 values at 7 stations increased while at other 11 stations decreased.Under A2 emission scenario,the average ET_0 values in 2011-2040,2041-2070,2071-2099 year increased by 2.7%,4.9%and 8.9%,respectively compared to the base period (1961-2000).The areas with largest increase of ET_0 were Ankang,Shiquan and Lueyang stations in Southern Shaanxi,Huashan station in Guanzhong,and stations in Northern Shaanxi.Guanzhong area performed smaller increase range.ET_0 values were predicted to change unevenly in 2071-2099 year with the largest increase in winter.【Conclusion】 The continued growth of ET_0 would increase the shortage of water resources in Shaanxi,further affecting the future water requirements of crops and irrigation.