Traumatic brain injury (TBI) is characterized by high incidence, high disability rate, and many sequelae. Depression after TBI is the most common sequelae of mental illness, which can affect the prognosis and quality of life of patients. The specific pathogenesis of post-TBI depression is not yet known, and there is no recognized prevention and treatment plan. This review aims to retrospectively summarize the epidemiology, risk factors, clinical manifestations, evaluation, possible mechanisms, and discoveries of treatment of post-TBI depression in the past 5 years, which will help clinicians manage this difficult disease more effectively and provide a reference for future research.