Urban green spaces function as a vital nexus concerning natural ecosystems and socio-economic systems, with their diverse ecosystem services offering crucial support in tackling urban ecological and environmental risks. Nonetheless, current research primarily concentrates on single-scale or isolated service analyses, thereby leaving substantial gaps in comprehending the multi-scale characteristics and influencing mechanisms of green space ecosystem services. This knowledge deficit significantly constrains their potential application in sustainable urban development decision-making. This study conducts a bibliometric review of relevant literature from the past two decades, analyzing research advancements on urban green space ecosystem services from the perspectives of spatial composition, service assessment, formation mechanisms, and supply-demand relationships. The results indicate that: (1) Over the past decade, there has been a significant increase in research in this field. Domestic studies tend to assess green space ecosystem services from the perspectives of urban planning and territorial spatial governance. At the same time, international research is focusing more on the intrinsic connections between these services and biodiversity, as well as human health. (2) Urban green space ecosystem services exhibit distinct multi-scale characteristics, encompassing street, city, and intercity levels. At the street scale, research focuses on microscale green spaces, such as pocket parks and street trees, assessing services like heat mitigation and stormwater regulation through field surveys and modelling. At the city scale, studies evaluate regulatory and cultural services of medium-scale green spaces using integrated models and multi-source data. At the intercity scale, research targets macroscale green infrastructure such as forests and watersheds, employing socio-ecological models to assess provisioning, biodiversity, and climate regulation services. (3) There are significant differences in the formation mechanisms and supply-demand relationships of green space ecosystem services across different scales. Street-level green spaces are small and fragmented, often leading to mismatches between supply and demand. At the city scale, mismatched spatial distribution results in service overload in central areas and redundancy in peripheral zones, with urban expansion exacerbating service fragmentation. At the intercity scale, supply-demand dynamics reflect complex systems of regional resource allocation and multi-stakeholder coordination. Future research should prioritize the development of multi-scale green space classification frameworks, the exploration of cross-scale service transfer mechanisms, the innovation of multi-source data integration methods, and the examination of scale-sensitive responses under interacting factors. These advances will provide a stronger theoretical and practical foundation for optimizing urban green space systems and promoting sustainable development.