China is experiencing unprecedented urbanization and aging. Previous studies mostly ignored the internal mechanism of the effect of urban green space on the mental health of older adults. Consequently, the relationship between social participation in urban green spaces and mental health remains uncertain. Therefore, this study explored the impact of urban green spaces, social participation, and other factors on the mental health of older adults and investigated the mechanisms of these effects. This study used linear regression models and conducted a moderating effect analysis using data from the 2018 China Labor Dynamics Survey, comprising 3501 older adults in 146 cities in China. Furthermore, we analyzed differences between solitary and non-solitary older adults. The results indicated that urban green space, road density, physical health, history of hospitalization, subjective well-being, and economic satisfaction significantly affected mental health. Social participation played a significant positive moderating role in the connection between green spaces and mental health among older adults. For solitary older adults, social participation weakened the positive impact of green spaces on mental health; for non-solitary older adults, social participation enhanced the positive impact of green spaces on mental health. These findings could contribute to the future construction of aging-friendly cities in China and help optimize urban construction and strategies for building healthy environments.

Against the backdrop of accelerating population aging and scarce elderly care resources and facilities in China, the issue of the sense of safety among the elderly has received widespread attention. This article is based on data from the China Labor Force Dynamics Survey (CLDS) in 2016 and takes three major urban agglomerations as examples to examine the impact mechanisms of urban built environments on elderly people’s sense of safety. The results indicate that the characteristics of the urban built environment, the social environment, and individual health affect the safety perceptions of the elderly. Among them, urbanization rate, hospital facilities, population density, greening rate, air quality, and frequency of dining out have significant impacts on elderly people’s sense of safety. Simultaneously, good daily exercise and mental health status can significantly improve elderly people’s sense of safety. This article summarizes the existing problems of aging-friendly spaces and facilities in three major urban agglomerations, proposes planning strategies to enhance elderly people’s sense of safety, and provides a useful reference for urban aging-friendly transformations and an elderly-friendly society.