The tableland protected region, as a major region for agriculture and habitation, plays an important role in the Loess Plateau. The information of the regional potential evapotranspiration (ET0) and its distribution on the Loess Plateau are beneficial to the reorganization in regional water cycle, control on the soil erosion and sustainable development of agriculture. Based on the meteorological data of the tableland protected regions of the Loess Plateau during 1960-2017, the spatial and temporal distribution of the ET0 and its controlling factors were analyzed by using the Penman-Monteith model, wavelet analysis, Mann-Kendall test and ArcGIS. The results are shown as follows: (1) The average ET0 of the study area is 1173.4 mm, which shows a significant increasing trend with a rate of 21.1 mm/10 a. The average ET0 in growing season is much higher than that in the non-growing season. (2) The spatial distribution of the multi-year annual average ET0 in the study area decreased from the east to the west, and the multi-year average ET0 in the western Gansu tableland is far lower than that in the eastern Shanxi tableland. (3) Over the past 58 years, the average ET0 of the whole study area, growth season and non-growth season showed a significant increasing trend, but the spatial variations are remarkable. There were 10-year, 30-year and 50-year oscillation periods in the variation of average ET0 in the study area, of which the 30-year oscillation is the main oscillation period during the past 58 years. (4) Air temperature is the most important meteorological factor controlling ET0 change in the region, but the influence of air temperature on ET0 change shows an obvious spatial difference. The lowest temperature has the most significant effect on the ET0 change of the whole study area. The changes of ET0 in the Gansu tableland and Shaanxi tableland are mainly affected by the change of average temperature. The change of maximum temperature in Shanxi tableland has significant influence on regional ET0. (5) The Pacific/North America index (PNA) and the Atlantic Multi-decadal Oscillation (AMO) are associated with the regional ET0 change, while the ET0 change of the non-growing season is related to the change of the WPI.