Frailty is a clinical syndrome characterized by a decline in the body’s physiological system reserve capacity. Its incidence is rising exponentially, seriously affecting the quality of life and health of the elderly, and even elevating the risk of mortality. This paper reviews the latest research progress on the concept, risk factors, assessment tools, possible mechanisms, and prevention of frailty, and highlights the challenges and future directions in identifying, assessing, intervening, and monitoring frailty. This article aims to help clinicians initially understand the concept, assessment, and prevention of frailty, so that they can actively and comprehensively intervene in frailty from multiple aspects, delay its development as much as possible, avoid adverse outcomes, and improve the quality of life of the elderly.