Abstract: Nonunion is one of the most common serious complications of fracture, with an incidence of approximately 4%-10%, which seriously affects patients' function, quality of life, and brings heavy social burden. Scientific and reasonable clinical diagnosis of nonunion is the basis for building the risk stratification and early warning mechanism, in which time diagnostic criteria are particularly important. Numerous exposure factors derived from the individual patient's circumstances, trauma, and medical interventions have been shown to contribute to the development of nonunion. Exploring these risk factors and the intrinsic correlation of nonunion, and developing a prediction model, are important means of early identification of nonunion.