Abstract-Ecosystems offer a wide array of benefits to support human livelihoods and enhance quality of life. Quantitative evaluation of Ecosystem services (ESs) is crucial for achieving the goal of sustainable development. The Yellow River Basin has a large population, and there are contradictions and conflicts in ecological protection, resource utilization, and economic development, among which the downstream region is the most prominent. However, the ecosystem services selected in existing research are not comprehensive enough, and there are also few studies that further focus on the effects of urbanization on this basis. This paper calculated seven types of ESs based on the InVEST model and related methods, and then constructed a composite ecosystem service index (CESI), and studied its spatiotemporal evolution and response to urbanization indicators through bivariate spatial autocorrelation and spatial metrological models. We found that from 1990 to 2020, the CESI fluctuated and decreased with time, with a significant positive spatial correlation, but showed a weakening trend. There were differences in the evolution process of the spatial correlation between the CESI and population density, economic density, and land development degree, but ultimately the spatial correlation changed from positive to negative. In terms of spatial spillover effect, population density had a significant positive effect on the CESI, land development had a significant negative effect, and economic density had a weak spillover effect. This paper provides a certain reference basis for governments at all levels to formulate relevant strategies for environmental protection and economic development.