Based on the daily observation data at six meteorological stations along the Yellow River Urban belt in Ningxia from 1995 to 2015, we estimated the potential evapotranspiration (ET0) and actual evapotranspiration (ET) using Penman-Monteith model and Budyko hypothesis, and analyzed the temporal and spatial distribution and changes of ET and ET0 using Morlet wavelet analysis, climatic tendency rate and other statistical methods. The results show that the mean ET0 of the urban belt from 1995 to 2015 was 831.585 mm and the mean ET value was 710.551 mm, ET was much lower than ET0. The relationship between ET and ET0 was in line with the hypothesis of proportionality, under the change of water supply conditions, both ET and ET0 showed an obvious increasing trend, presenting a positive correlation. The overall inter-annual variation of the mean evapotranspiration in each season showed an upward trend during 21 a, but it also presented obvious phase characteristics, which increased first, then decreased and then rose again. 2006 was the abrupt change year according to the sliding t test. The distribution of annual mean evapotranspiration and climatic tendency rate of the urban belt during 21 a presented a spatial pattern of “low-high-low” from northeast to southwest.