Abstract: Diffuse large B-cell lymphoma (DLBCL) is one of the most common types of progressive B-cell non-Hodgkin lymphoma and is characterized by strong heterogeneity. Its prognosis is influenced by many factors; hence, diagnosis for patients with high risk is important. This review discusses the prognostic factors affecting DLBCL patients on the basis of clinical factors, molecular biology characteristics, and PET/CT imaging according to domestic and global research progress.