Human activities directly or indirectly affect the changes in ecosystem services as well as the relationships among ecosystem services. However, the linear or non-linear relationships between human activities and ecosystem services are still unclear when considering large geographical differences. In this study, four ecosystem services (ESs), including habitat quality (HQ), soil retention (SR), water yield (WY), carbon sequestration (CS) and total ESs, were measured in the Belt and Road region in 2015. We mapped the tradeoffs among the ESs and the partitioned responses of the total ESs and ES tradeoffs in response to human activities (i.e., population density, GDP density, and nighttime light) using piecewise linear regressions at different scales. Then, the GeoDetector method was used to detect the major driving factors based on q value. The four findings were as follows. 1) The regions with low values for the 4 ESs were consistently distributed in arid areas, and the distribution of the areas with high values of the 4 ESs was clearly heterogeneous. 2) The responses of the total ESs to the GDP and nighttime light each had a threshold. However, there was a positive linear relationship between the population density and the total ESs throughout the region. At the national scale, the responses of the total ESs to human activities were more obvious in China than in Russia and India. 3) The thresholds of the impact of the GDP on the tradeoffs among the ESs were obvious. 4) Population density was a major driver of the ESs and the tradeoffs with q values greater than 0.4. The findings of this study contribute to the exploration of the influence of human activities on the total ESs and the tradeoff between ESs, thereby providing spatial indications for promoting the construction of a green Belt and Road region to support sustainable development goals.