Small-for-size syndrome is one of the most common and dangerous complications of partial liver transplantation. With the accumulation of clinical experiences and basic researches developed in recent years, new knowledge about the pathogenesis, pathophysiological process, prevention and treatment of small-for-size syndrome has been established. This article summarizes the progress of research on the small-for-size syndrome in recent years to help better diagnosis, prevention and treatment, thus improving the prognosis and long-term survival of patients.