Data from eleven meteorological stations in the Tianshan mountains and the north slope of west Kunlun mountains, and eighteen meteorological stations in the Kaidu-Kongque river, Akesu river, Kashiger river and Yankant river oases were examined to assess the differences in changes in potential evaporation from 1960 to 2006 in the mountainous and oasis regions of the Tarim basin and the relationships of these changes to meteorological factors. The decreasing trends in potential evaporation were primarily due to the decrease in the aerodynamic terms in both the mountainous and oasis regions, but the trends in the oasis regions were more pronounced. Based on the complementary relationship between potential and actual evaporation, the decreasing trends in potential evaporation appeared to be related to the increasing trends in precipitation in the mountainous regions and the increasing trends in water consumption in the oasis regions, thus reflecting the different impacts of natural changes and anthropogenic influences.