Abstract: The acute: chronic workload ratio (ACWR) is a new load management tool in recent years. Some studies believe that ACWR is a useful tool to identify athletes' injury risk, while other studies believe that there is no inevitable association between ACWR and injury risk. Moreover, different studies have not reached a complete consensus on the calculation method of ACWR. The aim of this study was to investigate the origin and development of ACWR, discuss the calculation method, function and possible mechanism of ACWR, and then provide suggestions for athletes' load management and sports injury protection. This study shows that: in team sports, (1) The best calculation method of the average load and time windows should be selected according to the sport-specific schedule of competition and training; compared with classification models, it is more accurate to analyze the relationship between ACWR and sports injury risk using a multivariate model with continuous variables, and (2) Higher ACWR may increase the risk of injury by increasing neuromuscular and psychological fatigue, while higher chronic load may reduce the risk of injury by improving the athlete's fitness.