Urban blue-green space is an important place for residents’ social communication activities and a guarantee for residents’ well-being. Previous studies focused on the influence mechanism of blue-green space on surrounding residents’ mental health and explored the mediating effect of social interaction and physical activity on the site scale. However, few studies have narrowed down to different types of social interaction; in addition, whether the mental restoration level affects social interaction, in turn, is often ignored. Therefore, this study divides social interaction into three types: passive, short-term, and continuous social interaction. Combined with the questionnaire surveys and field surveys of East Lake Greenway in Wuhan, extracted the relevant informationon space and residents’ social interaction, then established the correlation model between the two by using the SPSS macro program Process model 4to explore the impact mechanism and pathways of blue-green space on residents’ social interaction. Results showed that there is a significant correlation between the spatial characteristics of blue-green Spaces and social interaction, including accessibility, hydrophilicity, view width, facility diversity, spatial belonging, and green visibility, and the blue-green space have different influences on different types of social communication. In addition, blue-green space can affect social communication through landscape restoration and environmental construction: on the one hand, different from previous studies, this study found that blue-green space can improve visitors’ social communication intention by affecting their mental restoration level; on the other hand, it also found that the length of time visitors spend in blue-green space will also affect their social interaction level. This study explores the mechanism and pathways of blue-green space affecting residents’ social interaction level and provides a scientific reference for the construction of a healthy city.