Abstract: The "old drifters" are encountering challenges in integrating themselves into urban life and gaining a sense of belonging. Green space, as an important community resource, plays a critical role in enhancing the sense of belonging among elderly adults. By clarifying the extent to which perceived green space quality influences the sense of belonging among the elderly in communities and the mechanism behind this influence, it is possible to better formulate the policies of sustainable human environment development. By analyzing the questionnaire survey data collected from typical settlements in Nanjing, this paper examines the effect that the perceived quality of green space has on the sense of belonging to the community among the "old drifters" and the mechanism behind this effect. To achieve this aim, structural equation modeling was performed, with a sample of local elderly adults as the control group. The results are as follows: (1) Perceived green space quality exerts a significantly positive effect on the sense of belonging among the "old drifters" (β=0.189, P < 0.01). (2) Regarding this effect, a mediating role is played by green space use behavior, residence satisfaction, and neighborhood relationship. Among them, green space use behavior (30.76% efficiency ratio) exerts the most significant indirect effect on the perceived green space quality and the sense of belonging to the community among the "old drifters", followed by residence satisfaction (30.08% efficiency ratio). Neighborhood relationship (19.85% efficiency ratio) plays a critical role in the indirect effect of perceived green space quality on the sense of belonging to the community among the local elderly people. (3) Various individual socioeconomic characteristics exert a significant influence on the sense of belonging to the community among the "old drifters", such as length of residence, housing ownership, monthly income, and the participation in community activities. Finally, suggestions are made for enhancing the sense of belonging to the community among the "old drifters", and the prospects of future research are outlined.