Identifying the spatiotemporal variations in and driving factors of trade-offs and synergies among ESs in the plain area forms a critical foundation for the effective management of ecosystems and regulation. It is also crucial for effectively distributing the management of natural assets and the formulation of effective ecological policy. This research utilized correlation analysis, GWR and OPGD to examine the trade-offs and synergies among Net Primary Production, Soil Carbon, Water Conservation, and Habitat Quality in the Beijing Plain from 2001 to 2020. The results revealed that from 2001 to 2020, HQ and SC showed a declining trend, while NPP and WC exhibited an increasing trend. The trade-off intensities among NPP-SC, NPP-WC, and WC-HQ increased, whereas the trade-off intensities among NPP-HQ, SC-HQ, and SC-WC decreased. High-synergy areas for NPP-HQ, SC-HQ, and SC-WC were focused in the central urban area, with scattered distribution in the southeast and northwest. NPP-SC displayed a fragmented spatial distribution with significant variations. The spatiotemporal distributions of NPP-WC and WC-HQ were highly similar, both exhibiting strong synergy. However, NPP-WC demonstrated strong trade-offs in the northern plain area but weaker trade-offs elsewhere, while WC-HQ exhibited strong trade-offs outside the central urban area. The kind of land use was the primary element affecting the trade-off intensities of NPP-HQ, SC-HQ, and WC-HQ. NDVI and precipitation significantly influenced NPP-SC. The key factors influencing the spatial variation in NPP-WC were the land use type, temperature, and precipitation. Temperature was the primary determinant affecting SC-WC. The trade-off intensity among ESs is not determined by a single factor but is driven by the interactions between services or shared influencing factors, exhibiting high spatial heterogeneity. These findings provide valuable guidance for developing strategies for land-use planning and ecological restoration.