This study employs a quantitative approach to analyze the spatiotemporal distribution patterns of five ecosystem services in the Guanzhong Plain urban agglomeration, northwest China from 2000 to 2020. Utilizing K-means clustering analysis, ecosystem service clusters are identified, dominant service functions are determined, and ecological functional zones are delineated based on the functional characteristics within each cluster. Results indicate: (1) Grain production and soil retention exhibit a trend of initial increase followed by a decrease, while water yield demonstrates a rapid increase followed by a slow rise. Habitat quality and carbon sequestration services show a relatively mild decrease. High-value zones for grain production are concentrated in the central and northeastern parts, soil retention in the southern and western areas, and habitat quality and carbon sequestration services in the southern region. (2) Grain production shows a trade-off relationship with other services, while soil retention exhibits synergies with habitat quality and soil retention with carbon sequestration, as well as synergies between habitat quality and carbon sequestration, with varying strengths of inter-service correlations over time. (3) Ecological functional zones are identified as primary grain-producing areas, ecological conservation zones, important urban areas, and ecological balance zones. This study is crucial for maintaining the balance of ecosystems and fostering sustainable economic development, providing guidance for ecosystem management in different functional zones within the Guanzhong Plain urban agglomeration.