Ecosystem services assessments determine regional sustainable development and are critical to human well-being. This study took the Loess Plateau as the research area, based on the CASA, InVEST and RUSLE model, combined with the data of land use types, normalized vegetation index, meteorology and so on, analyzed the spatial and temporal distribution characteristics of the three key ecosystem services (NPP, soil conservation, and water conservation) in 2000, 2005, 2010 and 2015; and identified the hot spots of three ecosystem services, analyzed the trade-offs between different ecosystem services on the Loess Plateau and different climatic regions (arid, semi-arid, plateau and semi-humid climate zone) based on the correlation coefficient method. The results showed: (1) From 2000 to 2015, land use types in the Loess Plateau region changed drastically, among which forest land (2.8%) and construction land (43.1%) increased significantly, and cultivated land (-2.7%) decreased significantly. (2) From 2000 to 2015, all the average unit area of net primary productivity (NPP), water conservation and soil conservation showed an increasing trend, increased by 14.1%, 5.3% and 101.3% respectively. (3) The areas occupied by the four types of hotspots in the Loess Plateau (non-hotspots, first-type hotspots, second-type hotspots, and third-type hotspots) had not changed significantly, but the distribution had the obvious zonal distribution, that was non-hotspots, first-class hotspots, second-class hotspots, and third-class hot spots respectively from northwest to southeast. (4) Across the Loess Plateau, there was a synergistic relationship between soil conservation and NPP, soil conservation and water conservation. And there was a trade-off between NPP and water conservation. However, soil conservation and water conservation was trade-off in semi-arid and semi-humid regions, and the relationship between NPP and water conservation also was trade-off in arid and semi-arid regions. In order to promote the sustainable management of regional ecosystems, the relationships between ecosystem services should be considered in the land planning process, and trade-offs should be minimized and synergies should be maximized.