Urban forests are complex ecosystems created by the interaction of anthropogenic and natural processes. Two keys to improving the management of urban forest ecosystems are an understanding of their structure and its relationship to forest functions, and coordination of the management of the multiple functions of urban forests. As green infrastructure is an important part of urban systems, urban forests can provide a variety of ecosystem services. With rapid urbanization, increasing numbers of urban dwellers are facing health problems caused by environmental pollution. Therefore, the beneficial impacts of urban forests on human health have attracted increasing attention. Extensive development in Shanghai during the last few decades has led to rapid urbanization. The Shanghai Green Belt, with its many species and diverse vegetation types, is an important part of Shanghai's urban forests. After more than 10 years of construction and development, the Green Belt has become a major attraction for people who desire green space for recreation and relaxation, and it continues to have a positive role in the protection and promotion of the health of urban residents. Since the Green Belt landscape has increased in importance, its function in promoting human health should be evaluated to optimize its structure and to promote both its ecological functions and the related benefits it provides to people. Many research studies have demonstrated that the functions of urban forests that promote human health mainly depend on the vegetation type present, the vegetative community components and the structure of the plant communities present. In this study, typical plant communities in the Shanghai Green Belt were selected for analysis of their function in promoting a healthy human environment. This function was evaluated from the aspects of temperature and humidity amelioration, the generation of negative ions, bacteria inhibition, noise reduction, and air pollution reduction in summer and winter. The relationships between functions beneficial to human health and community structural characteristics and factors were analyzed, and the mechanisms influencing the function of forest communities in benefiting human health were explored based on the species composition and structural characteristics of these urban forests. The results showed the Taxodium distichum var. imbricarium Community, a deciduous coniferous forest type, has the best effect on most forest ecosystem functions related to human health with the exception of bacterial inhibition in summer. Two deciduous broad-leaved forest types, the Koelreuteria bipinnata var. integrifoliola Community and the Platanus × hispanica Community, have the least effect on promoting forested ecosystem functions related to human health, while other community types are in the mid-range. In winter, the evergreen broad-leaved forest Ligustrum lucidum Community has the best effect on such functions, followed by the evergreen and deciduous broad-leaved forest Koelreuteria bipinnata var. integrifoliola +Cinnamomum camphora Community and the Populus spp.+Cinnamomum camphora Community, and other communities types that have weaker health-related function effects. Correlation analysis between the functions related to the promotion human health and community structural factors shows leaf area index (LAI) and canopy closure were significantly and positively correlated with health-related functions, and LAI and canopy closure were important structural parameters that indicated the plant community provided important functions related to human health. By quantitatively evaluating the health-related functions of different plant communities in the Shanghai Green Belt, we explore the differences in different community types in the promotion of ecosystem functions related to human health. We also reveal the mechanisms influencing those functions, suggest some strategies related to optimizing plant community structure under specific environmental conditions, and provide a scientific basis for urban forest planning, design, and management.