To understand the current situation of social support and social isolation among elderly people in the community and their influencing factors, and to provide a reference for mental health interventions for the elderly based on the community, this study conducted a survey from June to July 2024 using cluster sampling. All eligible elderly people who participated in the physical examination at the community health service centers in two communities in Hefei, Anhui Province, were selected. The survey used the General Information Scale, the Lubben Social Network Scale-6, and the Social Support Behavior Scale. Logistic regression analysis was used to explore the influencing factors of social isolation among the elderly. A total of 304 valid questionnaires were collected, with a social isolation incidence rate of 36.8%. 59.5% of the elderly could obtain information support, 58.2% could obtain emotional support, 47.4% could receive evaluation support from family or friends, and 65.8% could obtain specific material support from family and friends when needed. Logistic regression analysis revealed that social participation [OR (95%CI): 2.56 (1.36~4.79)] and specific material support from family [OR (95%CI): 2.01 (1.11~3.64)] were influencing factors for social isolation among the elderly in the community. The research results indicate that the rate of social isolation among the elderly in Hefei's communities is relatively high, and the level of social participation and specific material support are the main factors affecting social isolation among the elderly in the community. Efforts should be made to strengthen social support and social network interventions for the elderly to improve their mental health status.