Urban green space is an essentially ecological spatial vehicle for the long-term strategic development of the Chinese cities. It is expected that future urban ecologically spatial design will heavily rely on the ecosystem service value (ESV) of green space in core urban zones. Trade-offs or synergistic relationships among ecosystems can be characterized by different land use patterns and intensity of use. In this study, the PLUS model was applied to the green space in the center of Zhanjiang City to simulate the land use changes by 2035 under the two scenarios of the natural development and territorially spatial planning. The equivalent factor method and hotspot analysis were used to analyze the spatial aggregation of ESVs as well as their high and low values. The spatial distribution of human activity intensity in the study area was overlaid to establish the priority zoning of urban green space development in the central urban area of Zhanjiang City under territorial spatial planning policy, to prioritize the resolution of conflicts between construction land and green space development, to provide a quantitative data base for the planning policy, and to provide data support and suggestions for its feasibility implementation, timing arrangement and expected results. The analysis results showed that (1) compared with future land use simulation results of the natural development scenario, there could be an increase of arable land and forest land, the overall water area could be effectively protected, and the spread of construction land could be suppressed. (2) The value of ecosystem services in the 2035 planning policy scenario > 2020 actual scenario > 2035 natural development scenario is approximately $1.222 billion, $1.189 billion, and $1.053 billion, respectively. The total ecosystem service value under the planning policy scenario could be about $169 million higher than under the natural development scenario. As a result, there could be significant improvement in ecological and environmental benefits. Meanwhile, the regulation service, support service, supply service and cultural service could improve by about 138, 13, 12, 6 million yuan, respectively. However, cultural service could reduce by about 31 million yuan compared with the status quo in 2020. Thus the creation of landscape aesthetics must not be neglected in the future planning and construction initiatives. (3) By analyzing the spatial distribution of ecosystem services and the intensity of human activities, and then zoning the priority of green space development, it is recommended that the central area of Chikan District, the construction land along the sea and water areas, and other areas should be zoned.