Introduction: Frailty is a multidimensional geriatric syndrome related to adverse outcomes. Social domains play an important role in the progression of frailty. Exploring social risk factors would be helpful to prevent frailty and disability. However, research in social frailty among older adults is still limited. We aimed to develop and validate a tool for measuring social frailty in Chinese older adults. Methods: We developed a tool—HALFT scale—to assess social frailty. HALFT scale includes the following five items: inability to help others, limited social participation, loneliness, financial difficultly, and not having anyone to talk to. Those who had more than three items were considered as social frail. 1697 community-dwelling old adults from Beijing Longitudinal Study of Aging (BLSA) with an 8-year follow-up were recruited. Cox proportional hazards models were used to evaluate the association between social frailty and adverse outcomes. Results: Older participants with physical frailty and worse physical function were prone to be social frail. Those who had dementia, subjective memory decline, depression, and cognitive impairment had a higher prevalence of social frailty. Cox regression analysis revealed that participants with social frailty were associated with a higher mortality (HR = 2.5-4.3). Key conclusions: HALFT scale is a useful tool to identify social frailty and can predict long-term mortality in Chinese older adults.