Green Lands in urban parks are important and indispensable parts of the contemporary cities. Whether citizens can conveniently enjoy facilities and services supplied by the urban parks is regarded as a significant indicator of the harmonious man-land relationship, urban modernization, and inhabitants' life quality. Furthermore, it embodies the social service function of the green lands in urban parks. This study selected Futian district as the study region. Single-point green land walk score was calculated to determine the walking accessibility of green lands. The population of Futian district was spatialized based on its land-use data. Combining the data of green lands and population distribution, this study evaluated the social service function of urban park green lands by determining the walking convenience of citizens in these green lands. Based on the isotropic area hypothesis, the overall walking accessibility of urban park green lands was found to be good in Futian. However, a huge difference was observed among different regions of Futian. A clear declining trend was observed from the eastern to the western parts of Futian. The green lands in Merlin Park, south Lianhuashan Park, Lychee Park, and Dahuang Park were considered highly accessible, whereas those in the northwestern and southwestern parts of Futian district were not. In addition, citizens could enjoy the services provided by these green lands conveniently and fairly in 70% of sub-districts; Huaqiangbei, Lianhua, Yuanling, and Huafu sub-districts had rather good open park space facility, and they performed a reasonable match between the green lands and population pattern. The status of green lands in the urban parks of Xiangmihu and Shatou sub-districts still needed to be improved. This manuscript presented a case study of the assessment of green land construction in urban parks using the walk score method. It particularly explored a new idea in applying walk score, providing useful reference for the construction of pedestrian city and spatial distribution optimization of green lands in urban parks.