Urban green infrastructure, as one of the main pillars of sustainable development, plays a fundamental role in improving the quality of life of citizens and achieving social sustainability. Despite the importance of this component, many Iranian cities, especially in old contexts, have faced challenges such as the reduction of local green spaces, erosion of canals and springs, and the decline of social interactions in recent decades. The present study aimed to analyze the role of urban green infrastructure in improving the social sustainability of historical neighborhoods in Hamadan. The research method is descriptive-analytical and applied in terms of purpose. A questionnaire was used to collect data, and the statistical population included residents of five old neighborhoods in Hamadan (Kalpa, Kebabian, Haji, Aghajani-beyg, and Khatuniyeh).The sample size was determined using the Cochran formula of 385 people and the data were subjected to factor analysis and structural equation modeling using SPSS and AMOS software. The results showed that there is a significant relationship between urban green infrastructure and dimensions of social sustainability including neighborhood identity, sense of belonging to place, social presence, safety and security, social participation, and access. Among these dimensions, "neighborhood identity" and "place attachment" have received the greatest impact from green infrastructure, while "social participation" has shown the least relationship. Accordingly, preserving and restoring natural elements such as springs, canals, and neighborhood lawns can be considered as an effective strategy in improving the quality of life and social sustainability of historical urban contexts