Recreational service that relies on ecological space is a vital contributor to improve human well-being. However, the spatial mismatch between supply and demand of recreational service poses a great concern in the Yangtze River Delta (YRD) region, primarily due to rapid economic development, urban expansion, population growth and other factors. It is therefore of great significance to explore the spatial variation of supply and demand relationships of recreational service for practically guiding spatial planning and management of regional ecological land in the YRD. Based on land use and gridded demographic data, this article proposed a spatially explicit approach to quantify and map the supply and demand relationships of recreational service in the YRD by considering the impact of different levels of ecological land accessibility. We also compared the supply and demand relationships of recreational service in 41 prefecture-level cities. The results showed that: (1) in 2015, the supply and demand ratio of recreational service was 1028% in the YRD, indicating that the supply was far greater than the demand for the service. There was also a spatial mismatch between the supply and demand of recreational service, where the supply-demand surplus regions were mainly located in the southern YRD, while the supply-demand deficit regions were primarily in the north. (2) With increasing ecological land accessibility from 0 km to 50 km, the proportion of supply-demand deficit area decreased from 43.1% to 7.8%, and the proportion of population in the deficit area decreased from 65.5% to 10.6%. (3) The 41 prefecture-level cities in the YRD were further divided into 5 groups according to their differences in the supply and demand relationships of recreational service. Based on these findings, we encourage that the decentralized allocation of ecological land should be promoted for the rapidly expanding urban areas of the YRD. It would also be beneficial for meeting the increasing demand for recreational service in different regions of the YRD through implementation of the payment for ecosystem service project between surplus and deficit regions in the future.