Separation anxiety disorder （SAD） has always been considered to be a mental disorder that occurs only in children and adolescents. There is increasing evidence showing that adult separation anxiety disorder （ASAD） is not uncommon. In the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders （DSM-5）， ASAD was included in the diagnosis of mental illness for the first time. However， so far domestic and foreign studies on the pathogenesis， treatment and other aspects of ASAD are extremely limited， further more， domestic related studies are almost zero. Due to the lack of appropriate treatment guidelines， psychiatrists rarely diagnose ASAD alone. This article mainly reviews the research status of ASAD pathogenesis， diagnosis and treatment