In order to have a thorough recognition of the variation characteristics and influencing factors of potential evapotranspiration (ET_0) in Shaanxi Province under the climate change. Based on 20 meteorological sites of daily weather data from 1955 to 2015 in Shaanxi Province,the Penman-Monteith (P-M) is utilized to calculate the potential evapotranspiration (ET_0). The spatial and temporal variations of annual and seasons ET_0 are analyzed by using cumulative distance,Mann-Kendall mutation detection,the optimal partition method,inverse distance weighted interpolation (IDW) and other mathematical methods. The dominant meteorological elements influencing ET_0 are quantitatively studied by using partial correlation and multiple regression models. The results showed that the annual ET_0 of Shaanxi Province from 1955 to 2015 presented slight rising trend with the rate of 1.03 mm/decade. ET_0 changed as the inverted S-shape over the periods. The average ET_0 rates in spring, summer, autumn and winter were 3.72 mm/decade,0.12 mm/decade, 0.36 mm/decade and 2.95 mm/decade. The spatial distribution of annual and seasonal ET_0 in the study area was significant variation pattern of latitudinal direction zonality. The main impacting factor was average temperature in spring,autumn and winter, but was sunshine duration in summer. The above results indicated that the ET_0 in Shaanxi Province had the characteristics of stage and zonality,influencing factors had the seasonal characteristics. The results would provide valuable information for water resources optimal allocation and assessment in Shaanxi Province.