Frailty, a common geriatric syndrome, is a serious problem in healthy aging. However, its pathogenesis remains unclear. It is a general agreement that frailty is caused by multiple factors, in which immune dysfunction and chronic inflammation play an important role. Because gut microbiota is associated with immune function and chronic inflammation, the correlation between gut microbiota and frailty has drawn increasing attention in recent years. This article mainly introduced the progress in the research of gut microbiota in the frail elderly, providing the reference for the pathogenesis of frailty.